#305 - Heart rate variability: how to measure, interpret, and utilize HRV for training and health optimization

Peter Attia
Hey everyone, welcome to the Drive podcast. I'm your host, Peter Attia. This podcast, my website, and my weekly newsletter all focus on the goal of translating the science of longevity into something accessible for everyone. Our goal is to provide the best content in health and wellness, and we've established a great team of analysts to make this happen. It is extremely important to me to provide all of this content without relying on paid ads to do this.

Our work is made entirely possible by our members, and in return we offer exclusive member only content and benefits above and beyond what is available for free. If you want to take your knowledge of this space to the next level, it's our goal to ensure members get back much more than the price of the subscription. If you want to learn more about the benefits of our premium membership, head over to Peter attiamd.com subscribe my guest. This week is Joel Jameson. Joel is the CEO and founder of Morpheus Labs, and eight weeks out, Morpheus Labs aims to work with trainers and individuals to maximize training results using a combination of data, science and physiology, primarily through heart rate and heart rate recovery training systems.

Joel Jamison
The system is used by a number of professional sports teams in the NFL, NBA, MLS, NC, two A and more. Eight weeks out is a company that helps coaches, athletes, and fitness enthusiasts improve their strength, conditioning and performance. In this episode, we speak about what sparked Joel's personal interest in the world of heart rate variability and the history of heart rate variability development over time. We break down the science of HRV and how HRV is calculated. There are many different methods and how the interplay between the sympathetic and parasympathetic nervous system affects your heart, the reliability of tracking HRV, and ultimately what it is that HRV is telling us about these autonomic nervous systems.

We talk about the decline of HRV with age and what drives this change, and how much of it is within our control versus genetically predetermined. We then talk about Morpheus, which is a product that ultimately led to my meeting Joel. We talk about my skepticism around Morpheus when I first began to use it, and ultimately why I came to believe that it is a really valuable tool for people when they're training, especially people who might not be as interested in, for example, using lactate testing or other really advanced forms of testing to fine tune their training zones. We talk about the impact of lifestyle choices on HRV and its significance for overall health, and how to use the data from HRV to inform daily choices. Finally, we talk about HRV within the broader context of other health metrics and where it sits in the hierarchy of measurable insights.

A final point I'd like to make is that while we speak extensively about Morpheus, I want to make sure everybody understands I have no financial affiliation whatsoever with Morpheus. I'm not an investor in the company. I'm not an advisor to the company. We have no affiliate deal with Morpheus. Of course we have no affiliate deal with any company.

In other words, there is no financial remuneration of any sort that exists between me and this company. I am simply a huge fan of this company and I speak about it often, recommend it to a number of my patients because of my belief in its efficacy in helping people achieve their exercise goals. We do discuss a couple of other companies in this podcast that I do have relationships with. These have been disclosed previously, and they're all on my disclosure page, but I would like to again reiterate them here. I am currently a scientific advisor to the company eight sleep, and I am a passive investor in the company aura.

Those two companies do have a mention in this podcast as well, so without further delay, please enjoy my conversation with Joel Jamison.

Hey Joel, thanks for coming out to Austin. Been looking forward to this discussion for some time. We've not met before, but had what seems like an endless stream of email communication. So I always appreciate your willingness to not just respond to all my questions, but the thoroughness with which you do. So this is a topic that, as we were discussing just a few minutes ago, I think everybody has heard of it.

People have a vague sense of what it is, but once you get beyond a very superficial description of it, most people, I think, don't really understand it, and certainly most people don't understand how to use the data, and I would absolutely include myself in that category. So the topic, of course, of heart rate variability is near and dear to your heart. Maybe before we dive into the weeds of this stuff, maybe just give folks a bit of a sense of your background and what brought you to the study of this and over what period of time. It's really interesting to me to see the growth of it because I've been using it now for 20 years, and the story of it's really fascinating to me because I was in my early twenties and I had just graduated from University of Washington, interned there and done some strength conditioning, and then was progressing to the Seahawks to work with the same coaches. And there was a track coach named Randy Huntington, and most people probably never heard of Randy, but he was the USA track and field jumps coach.

Joel Jameson
He coached Mike Powell who broke Carl. Luce's long jump world record in 1993, something like that. Randy was around for a long time. He was a tremendous coach, and he was from my area. And I just kind of was talking to him one day, and I asked him some general advice as a young coach, what would you suggest?

And resources and all sorts of stuff. And he writes a phone number down for me and says, you need to call this guy. And I was kind of like, okay, whatever you say, randy. And so I call this guy, and this thick russian accent answers the phone and says his name is Val. And I still don't really know what I'm calling this guy for.

I just know that Randy told me to. And so he says, I'll be in your area. I'll meet you at the airport. I'm like, okay. I'm just kind of playing along and I'm not really sure what the whole point of this is, but Randy says, call this guy.

So I call this guy and he just says, I will show you the technology. And I'm again kind of like, okay. So I go down the seatac airport and I see this kind of big russian looking guy with a trench coat. I mean, it looks like he could be straight out of a movie, introduce himself, and he's like, lay down on the couch. I hope you're now out of the airport.

Or no, I mean, I'm in the hotel by the airport. And so again, I'm just in the dark of what is going on. And he says, lay down on the couch. And so I lay down on the couch and he's like, take your shirt off. At this point, I'm looking around like, is there some kind of practical joke?

Like, is Randy just messing with? This is when you have a lot of faith in Randy. He doesn't have a lot of faith in Randy and paid off. And so he does this big briefcase, and he pulls out this big laptop, and he starts plugging in wires and all this sort of stuff. And he pulls out these electrodes, he starts putting them on my chest, and he does basically an ECG ask me birthday and weight and all this sort of stuff.

And he's like, don't move. And so I sit there for two and a half, three minutes, and I see all this stuff on the computer happening. And again, still just completely in the dark. What is this guy doing to me? I have no idea.

And after about three minutes, hes, like, finished. And he starts telling me about my recovery status and my readiness, my metabolic profile, my central nervous system starts talking about all this stuff that didnt really make a whole lot of sense of how he would know. And he was like, youre much more strength oriented, and your cardiovascular system is not very good, which is accurate at the time. Maybe didnt take a computers see that, because I was definitely on the strength side. But he started just telling me the story of HRV and heart rate and variability.

And this was, again, 20 plus years ago. It was not something that people were aware of, and I had never, of course, heard of it. And the idea that you could take something out of a laptop, connect it to my body, and have any idea of physiologically what I was as an athlete or as a human being was completely new and seemed foreign to me, and immediately was like, I need this, because it seemed to me like theres so much of a black box when it comes to fitness. Sometimes I do a workout and I get better, sometimes I do workouts and I don't. Why?

What is the right magic answer here to always get the workouts that I want to see are the results? And so he started talking about the story of heart rate variability. And this is really fascinating because you don't read this when you look at the western literature, so you probably know it goes back way 17 hundreds. They're aware of b, two b intervals. Chinese have used pulse medicine a long time, but the Russians were pretty ahead of the game as far as application of HRV.

So in the 19, late 1950s, they were aware that from an ECG, you could pull out these BTB intervals and get something more than just heart rate. And so when they send the first human being in space, Yuri Gagarin, they were able to send back the ECG and some respiratory data and see fundamentally what happened to people when you shot them into space, which they really didn't have a way of gauging without this. And so they saw as soon as he went into space, his HRV went way up, probably because you have changes in blood pressure, you'd have less gravity, so you don't have to have as much muscle activity. And they started using this literally all the way back in the 1960s, which is pretty fascinating because you didn't really see that in the western literature for decades later, really in a meaningful way. Then in the 1980s, they were dominant as far as all the Olympic sports, right?

They just crushed us. Now they had a very elaborate drug program, they had very training program, they had a lot of different things that gave them the advantage. But in the mid 1980s, they started basically figuring out, can we use this tech for sport performance. And so they put together an engineering team, and they started collecting data on thousands of russian athletes of all levels, from their school age kids all the way up to their Olympic athletes. And they collected just populational norms, and they started building the system that was meant to monitor training and be used for this purpose.

Don't get me wrong, they had really high volumes, but they did blood monitoring weekly or monthly. They were constantly testing. From an organizational standpoint, their communist structure gave them a very hierarchical way to organize the source stuff and monitor it. So anyway, they spent years working on this platform, and then before they could finish it, the Soviet Union collapsed, and the whole team that was involved in this just dispersed and left Russia. And just by chance, a lot of them had been involved in track and field, different sports.

They end up reconvening in a track meet, Eugene, and kind of just talking about this path project, and they decide that they want to get together and keep working on this because they never brought to fruition, and they did. And that was ultimately the first system that I think was available. I mean, it was the first system that was available commercially with the intent of being used for sport and fitness. And that was what I was being introduced to at the time. This was the result of this project being finished.

The problem is they wanted $35,000 for it. It was a very research heavy medical type system that was not easy to interpret. I didn't have $35,000, but I convinced them to let me help them introduce it to teams across the US and gain some exposure for them as we worked at ideal. And I started using it. But it gave you twelve or 14 different metrics of heart rate variability.

It required you, like I said, connect electrodes to people before you'd measure them. And really it was that introduction to it where I started this whole journey, and 20 years of looking at data and coaching people and trying to understand what the data was telling me and how it aligned with all the other metrics has really just led me down this path of, of how you get tired variability today. And its certainly been a large change, but its kind of that crazy journey of starting one day in a laptop in a hotel next to the airport, and now its on everyones phones and watches and everything else. But I spent, like I said, 20 years coaching with it. And thats really the difference is I was a coach, I opened a gym, I worked with lots of fighters and athletes and different teams and military groups using data, looking at HRV, the whole nine yards.

So it's been a long time, but it's really fascinating to see it grow. So let's talk a little bit about the actual measurement. So, in the example you gave when you were first introduced to it, it was done off an EKG. I assume three leads would be sufficient. It was six back then, but you can certainly get it from three, obviously.

Joel Jamison
Yeah. So would we say, Joel, that that's still the gold standard for how to measure HRV? Absolutely. I mean, if you're talking about medical grade research quality, you want the cleanest signals. You want the most signals.

Joel Jameson
ECG, three lead, six lead is by far the way to go. This might be a little too in the weeds, but given how technical this topic is, do you want to explain how an EKG works? Because I think it will be relevant to distinguish between what an EKG is doing, what a chest strap is doing, what an optical sensor is doing on the forearm, on the wrist, or on the finger. These are all going to be basically the tools that technology companies are using to measure HRV. But as you and I have discussed and gone deep on this, there's a total difference in the fidelity of the signal depending on where the signal is acquired.

Joel Jamison
And given that our audience here is an appreciative audience for nuance, I think it might be worth explaining, from the gold standard all the way down, how these signals are acquired, what's happening physiologically and electrochemically, that's enabling the capture of the signal? Sure. I mean, you can kind of group these into two things, right? One is the electrical signal of the heart itself, and that's what we're measuring with an ECG or Ekg or the chest strap. You're literally measuring the polarization, repolarization of the heart as the chambers are beating, and you get this electrical signal that gives you the QRS complex.

Joel Jameson
And we're honing in on where those b two b intervals are, because ultimately, to get HRV, we need the exact amount of time from one heartbeat to the next, because that's what we're quantifying. You have electrical signal, you get a very clear, clean signal that you can pull out those exact beat to beat intervals. And that's where we fundamentally get heart rate variability from. Is it always done r to r? Because that's the cleanest signal?

Yeah, it's always done r to r. So you just have to be able to identify where is the peak of the r interval, the more accurately you can identify. Here's the peak of the r wave. Here's the peak of the r wave. The more accurately, you can get that.

Joel Jamison
And if my memory serves me correctly, because it's been so long. Right. So the p is the polarization of the atria and then the qrs is the ventricular. Is it the repolarization or the contraction? Maybe it's the contraction, yeah.

And then the t wave is the repolarization. Exactly. So you're basically, the r wave is giving you. If my memory serves me correctly, I'm sure there's a cardiologist listening who's going to scream right now. But that's the peak electrical signal of the contraction of the ventricle.

Joel Jameson
Exactly. Yeah. I'm not a cardiologist either, but from my memory, that's correct as well. But, yeah, you're getting this exact electrical signal that's showing us where that peak is happening. And because it's at high resolution, it's electrical.

We can pick that out pretty easily. Especially the more leads you have, the more you're going to be able to get that, the difference between that and an optical sensor. And tell me, by the way, if I'm wearing a polar chest strap, which is what I wear when I'm on my bike, I have a chest strap. How is the fidelity of that compared to an EKG? It's pretty close, honestly.

It's very close. As far as picking out the actual peak of the r wave, it's going to be within a millisecond second, which is more than enough. Now, obviously, if you have a full six late EKG, you're going to get even more, but you don't need it for HIV, as long as you can identify that peak of the R wave precisely within one or two milliseconds of what it's actually at. And that's where the gold standard is, is from the ECG. And just to give folks a sense of that, a millisecond, a thousandth of a second is the unit that HRV is typically being measured in.

Joel Jamison
So if a person is looking at their HRV and they're seeing a number that says 60 milliseconds, you're saying with a chest strap, you would put a plus or minus of one or two milliseconds on any reading that comes out. As long as it's a good chest strap. Now, the caveat is good skin contact and those sorts of things, if it's moving around or it's not in the right place, you can lose some of that, which, of course, you have a better chance of getting the signal correct with actual electrodes. That is really the gold standard. And that's how it was done for decades.

Joel Jameson
And that's how most 90 plus percent of the research has been done with either the EKG or with chest straps because that's really been the gold standard of how it's measured. The use of these PPG or optical sensors really has only been the last five, six years they've been around. And traditionally, their accuracy was just questionable when it came to it. And they don't get the same electrical signal. They're measuring changes in blood volume through the skin.

Basically, electrodes shine the led light down into the skin. It reflects differently based on the blood flow flowing through the arteries below it. And so youre getting the pulse. And they actually call it pulse rate variable. Its not really heart rate variability if we want to get technical, its pulse rate variability, but its showing us the same thing.

Its showing us that cardiac cycle. Now, there seems to be a big difference between the wrist and the forearm. So on my bike, if Im riding indoors, well, actually Im doubling up. So I'm wearing, people are going to be like, what is wrong with this Peter guy? He has so many stupid devices.

Joel Jamison
It'll all come to full circle through this. When I'm on my bike indoors, if I'm outdoors, I'm just wearing my polar chest strap because it pairs perfectly with the system. With the bike system I'm using outdoors indoors, I ride with my Morpheus chest strap and my wahoo optical sensor. The reason is I'm using two different programs. The wahoo sensor on my forearm, which is optical, is pairing with my computer and that program I'm using there in Erg mode.

But the reason I'm using the Morpheus chest strap is I'm using the Morpheus program on my phone. But the reason I bring all that up, Joel, is to say they're perfectly in sync. The chest strap, the gold standard, and the optical sensor on my arm, never off by more than a beat. And I can see them in real time concurrently. Conversely, when I'm rucking, when I'm putzing around, I wear a Garmin GPS watch that measures heart rate.

It's a very high end watch. It's about a $700 watch. It is categorically a piece of garbage. I would call it a random number generator for heart rate. It can't come close to estimating my heart rate.

There are times I look down and it says I'm at 170 beats per minute when I know I'm below 100. Conversely, there are times when I'm probably at 160 beats per minute. And it says, I'm at 110. So as far as I can tell, it serves absolutely no purpose. Occasionally it's accurate, I'm sure, but it's so inaccurate so often that I would never rely on it.

I'm using it for GPS, almost annoyed that it's a feature that is there. They're both optical sensors. Why the difference? Yeah. One is location.

Joel Jameson
As you mentioned, to get a good resolution, you need good blood flow below the surface, and you need the lack of movement. The biggest problem with PPG sensors, optical sensors as a whole, is they get what are called motion artifacts. And any kind of movement starts introducing noise in the signal, because, again, we're not getting electrical signal, we're just getting this blood flow going beneath the surface that we're using leds to detect for heart rate. When you start moving around, you get lots and lots of motion artifacts, and it just becomes much more difficult for those sensors to detect it accurately, particularly in, like, acyclical movements. Anything where your arm is moving around at random, higher heart rates, darker skin colors, lots of things throw off PPG sensors.

Joel Jamison
So my darker skin is obviously a. Disadvantage, presumably just in general, tattoos, all of these things. So optical sensors in particular, struggle with higher intensities, higher movements, higher heart rates, all those sorts of things. Now, my optical sensor on the bike, even though it, admittedly I'm not really moving, my upper body isn't obviously moving. Is it superior because it's less movement, or is it superior because it's on much larger?

Joel Jameson
Both, right? Yeah. So there's a company called Valensal that we use. It's done a lot of research on this because they produce the sensors and they've looked at any location, bicep, arm, calf, all of the above, even your wrist, you have bone movement. Even if you're not really moving, your wrists can still be flexing and extending in just that wrist movement will cause motion or effects.

You get much cleaner blood flow on the forearm. You get just much less movement and torsion as you're moving. So you get just a much better overall signal on the forearm in general than you're going to get from the wrist. They've looked at accuracies of garments and whoops, and you don't get very good accurate data at all, as you've seen when you're doing exercise, and even when you're doing somewhat cyclical exercise, you can still get, as you've seen, completely garbage numbers that make no sense because the sensor just cant pick up the blood flow very accurately and like I said, tattoos, dark skin makes it far worse. So in general, this test trap is always going to be the gold standard.

But if youre going to wear an optical sensor, the forearm where you can get good blood flow is going to be by far the best place to be able to put it. And you can even manipulate where in the forearm you tend to get the best signal, the best results. Yeah, I dont know if Im doing it correctly, Joel. I tend to apply it right beneath the antecubital fossa where I know the artery is running. Yeah, that's what you want.

Joel Jamison
And I'm sort of like assuming that I'm going to get the best signal there. And I also put it on pretty snug. I mean I was just doing that not thinking about motion artifact. But it sounds like that you would. Encourage that you want good enough skin contact that I can read.

Joel Jameson
You don't want to smash it in there. I'm not using is a catsu band. Yeah, exactly. Not doing bfs. If you start getting a forearm pump then you probably have a little too tight.

Joel Jamison
So it's almost like there's really three. I know you said there's two buckets. You could really say it's anything on the chest. Amazing. Gold standard, always going to be good as long as anything on the forearm.

I think we've established if you do the forearm right, at least heart rate to heart rate is comparable. We'll talk about the HRV variability and then anything below the forearm is sort of nonsense. It's not great. It's definitely not great, especially if you're lifting weights. If you're doing interval training, if you're doing anything high intensity, you're doing change of direction.

Joel Jameson
It's garbage. You just get very poor data and I wouldn't rely on it. It might be accurate sometimes, and sometimes it'll be way off the one that seems to be, I wouldn't say accurate, but the most accurate, the less accurate is the apple Watch. And I think what they're doing, since they have ECG, I think they're just interpolating a bunch of data. So when they see bad data, they just kind of replace it with what they think the data actually should be.

Joel Jamison
I see, so you're saying the Apple Watch might be a step ahead of other risk based devices based on sampling an algorithm you can detect when the. Junk data is there. You don't have to display it, the other ones do, but they have enough previous data to know that your heart rate didn't go from 110 to 160 in 2 seconds. So I think they'd start build the algorithm out to interpolate that. Yeah, it's odd that Garmin tolerates that, for lack of a better word, because I'll see it do that.

Right? I'll see it go from 100 to 150 and I'm like, that's not even physiologically possible. Why wouldn't you sample that out or ask a second order question? Yeah, great point. Okay, let's now talk about the very confusing subject of how one calculates heart rate variability, because let's again reiterate what we're talking about.

So if anybody has seen an ekg, everybody watching us has. You've got your little p qrst and you just line up a strip of those and you imagine you were doing this in the olden days. You'd have a set of calipers, you'd literally measure across r to r to r to r. So let's pretend we have a minute's worth of data, Joel, and a person's heart rate is they're laying down and resting, so they're at 60 beats per minute. So the approximate beat to beat interval is 1 second.

Joel Jameson
On average? Sure. Yeah, on average or 1000 milliseconds. Whats happening at the physiologic level that makes it such that there is variation? And how is that measured and calculated from the raw data?

Joel Jamison
And lets start with the gold standard and assume you have an ekg. Yeah. As you mentioned, youre starting with this gold standard of we can accurately pinpoint where are these r to r intervals. And so we pull out what are called the rr intervals, surprisingly, and well plot those. Now from there you do whats called correction.

Joel Jameson
Basically you have to filter data there for filter topic beats, which are beats that don't actually arise in a sinoatrial node. You fill out if there is any noise in the signal or anything like that and you end up with this clean set of rr intervals. So let's say I gave you 60 of them and it's, again, it's a person who's at rest. So on average it's 1000 milliseconds between them. But I'm going to give you 60 numbers that vary from 900 to 1100 milliseconds.

So this is where things get interesting because when we talk about HIV, we just usually give a number and that number can be different. But a better way to think about HRV is just a framework to assess variability because there are multiple ways to calculate that. There's one category called time domain where we literally just do some math. The most common one is RMSSD. Root means successive squared differences where they just do some basic math and they get that number of milliseconds of RM SSD.

There's SDNN, there's PNN 50, there's all these different column time domain where they just are taking that time series, doing some math on it, and giving you a number that represents the average variability. So let's talk about the RMSSD, because it appears to be the most common one. It is most common for multiple reasons. What we are, again, measuring is that average variability across that time span. And what that represents is the input of the vagus nerve of the parasympathetic system and its input into that sinoatrial node of the heart.

Because fundamentally, the autonomic nervous system is governing that heart rhythm. And primarily, what happens at rest is it's that parasympathetic system via the vagus nerve. And the way that it works is it's innervating that sinoatrial node in the heart, and it's pulsing in beat with respiratory processes. So as we inhale, that vagus is inhibited, and you get kind of this acceleration of heart rate. Actually, I should back up.

If you were to cut out the autonomic nervous system, you'd have roughly an intrinsic heart rate of about 100 beats per minute, somewhere in that range. Lets back up even a little further. Joel, I think theres a lot that you and I would take for granted here. So sort of nervous system 101. We have two nervous systems.

Joel Jamison
Broadly speaking. We have one thats under our control and one that is not. Most of what you and I are doing, that people can watch the movement speaking all of these things, thats voluntarily under our control. But what most people cant see when theyre looking at themselves is how many things are happening without any input. And thank God for that system.

That system happens to be called the autonomic nervous system. Without it, we would forget to breathe, and we would die. Our heart would stop beating. So all of these vital functions, from respiration to heart beating to regulating blood pressure to digesting, have to happen via a nervous system that we never think about. That system is further subdivided into the two terms.

You've already brought up a sympathetic system and a parasympathetic system. And youve already alluded to one of the most important nerves in that parasympathetic system called the vagus nerve, which is a cranial nerve, so originates from a very primal part of the brain, and we wont necessarily get into all the neurotransmitters involved in these things. But what youre basically describing is that the heart is under the influence of both of these. Exactly. An example that gets to your point is, after a patient has undergone a heart transplant, as an extreme example, that vagus nerve is transected, their heart is no longer under that control, and therefore, it's just going to have, and you.

Joel Jameson
Would see a heart rate variability of basically zero in that scenario, because it would just be like a metronome. Yeah. Okay. So didn't mean to interrupt, but I think that might be just helpful context for people to sort of understand what we're talking about, which is you're talking about even though that person's heart is beating at 60 beats per minute, there's still a very fine interplay between what the sympathetic nervous system is doing and what the parasympathetic nervous system is doing. Yeah, we should probably even back up a little bit more.

The whole reason that we need this autonomic nervous system is to keep us physiologically within these normal ranges that we have to be in to be able to produce energy and stay alive. Right. So if our blood pressure goes too high or too low, if our blood glucose gets too high or too low, if our body temperature gets, all of these things have to be within physiological norms. And we'd call that homeostasis, that the internal environment has to be controlled at all times, regardless of the external environment. So whatever temperatures we're in, whatever we're eating, whatever we're doing, we have to be able to regulate internally and stay within these physiological norms that are necessary for survival.

And that, fundamentally, is what the autonomic nervous system is doing. It's keeping us alive, and it's trying to match the internal demands with whatever we're trying to do, given the external environment. So, like you said, people have heard of probably these two branches, the sympathetic, the fight or flight, or the parasympathetic, which people call rest and digest. Now, thats a good terminology to understand, but it makes us only think of the sympathetic. Its not nuanced enough.

Its not nuanced enough. It also makes us think the sympathetic isnt doing anything unless youre under stress, right? Its not really like that. These things arent binary. Theyre not switches that turn on or off.

A better way to think about these is dials that the brain is constantly manipulating. Fundamentally, what the autonomic nervous system is doing is twofold. One is it's sensory. A lot of information has to go up to the brain to process what the internal environment status is. And then the brain has to make decisions and push motor action down to the different organs to make sure that they're doing what they need to do, given the state of the body, given its external relationship with the world.

So fundamentally, the more we can regulate our internal environment and match the demands of our external environment, like, the healthier we're going to be, we're going to be more adaptable, we're going to have better overall function. We probably would just say it's broadly better health. And so the interplay between that sympathetic and that parasympathetic and making sure they can do their jobs appropriately is a really big piece of making sure that our bodies are going to stay healthy as we age. Because I would say fundamentally, if we look at aging as a whole, we lose adaptability, we lose the ability to respond to workouts as quickly. We become more likely to become injured when we get sick.

It takes longer to get over that, and that's just the body's ability to regulate itself declining with age. So, anyway, with that said, at rest, we should have very little sympathetic activity going on. And we can talk about this in terms of waking versus sleeping. Those are different things. Yes, I want to talk about that.

We have a pretty low level of sympathetic just sitting down or laying down. And at rest, that parasympathetic dial is going to be higher because we don't need this additional energy that the sympathetic system can drive. So at rest, we're primarily measuring that parasympathetic input into the heart. And as I mentioned, it turns on and off with our respiration. It's called respiratory sinus arrhythmia.

And as we exhale, that dial turns up just slightly, and as we exhale, it turns down just slightly. But mostly what's happening is we are inhibiting that vagal input as we breathe in, and we're letting it function correctly or not correctly, but we're disinhibiting it as we breathe out and as we exhale. And so youre seeing just this pulsation type effect of that vagus nerve on the heart rate accelerating and then slowing down and then accelerating and then slowing down. So youre seeing that input pulsing with our respiratory cycles. And so when we measure HRV, regardless of how we do it, were ultimately trying to understand that tone.

We call it vagal tone, that input of that vagus nerve into the heart rhythm. And that's what we're trying to then gauge as a functional marker of what our autonomic nervous system specifically, the parasympathetic nervous system is doing. How is it responding to the world around us? How is it responding to what we've done in the last 24, 48 hours? What is its resting tone?

How much input does it actually have? And from that we then try to gain all the other insights we can talk about. And then just to close the loop on the measurement thing, most people are using devices that are probably calculating the HRV on the RMSSD algorithm. Yeah, most of the commercial ones. Yeah.

Joel Jamison
Its a transformation thats basically run on the data. If my memory serves me correctly. I mean, we could figure it out, right? Root, mean square or the standard deviation. Successive squared.

Successive squareds of standard deviation. So youre basically going to say average or mean value is x standard deviation is this. And then you probably do a sum square, square root of. Exactly. Yeah, you get your number.

Joel Jameson
Now the only one I would say that's different is Apple Watch. Actually. They use what's called sDNN, which is just the standard deviation of the BTB intervals. Why they do that, I'm not sure. That's one that's historically been used medically.

And they'll usually measure it for 24 hours and they'll just kind of look at like, do you have any autonomic variation? Does the parasympathetic system function well at all? And it's kind of a gross measure, is not nearly as nuanced because we're not measuring vagal input at a particular time, we're just measuring across longer periods of time. And maybe that's why they did that. It seems to me that that would also introduce a bit of noise because you're combining being at rest with being active.

Yeah, exactly. And you would, I don't know if it's the right word, but you'd be penalizing people for being more active because the more you exercise, the more sympathetic toned you have during exercise, the more you're crushing the variability. What's interesting is Apple is just kind of measuring randomly. For the most part. It just kind of measures when you don't know.

And you can do a manual measurement, which we can talk about, and you can actually check it, which is a better way to do it. But for whatever reason, they've just used this metric that nobody else uses, and then they kind of measure it periodically when you don't know what's happening until the number, you're just kind of getting in there. If you're not actively measuring, it is just kind of like, I don't know where it comes from. So a couple of things that I remember from a AMA that I did on heart rate variability a couple of years ago, and we'll link to it here in the show notes so that people can go back if they want a real primer on HRV. The reason we did sort of an AMA on that, a lot of people had questions about it.

Joel Jamison
Frankly, I don't think we went into nearly this level of detail about it. We talked much more about the mortality data and things of that nature. But that was one of the first things that stood out. Two things I remember more than anything, Joel. The first is there was a relationship between, in the research literature, what was measured as HRV.

We should talk about what that means, and all cause mortality and even disease specific mortality. And the second thing that really stands out is a graph that I'll never forget that shows on the x axis, age on the y axis, HRV, and what the curve looked like. And I couldn't believe how steeply it declined. Right. And I think what it was plotting, if I'm not mistaken, was kind of mean or median HRV with a band of, call it the 80% or interquartile range or something like that.

But it was an unmistakable trend, which is like a 50 year olds HRV is less than half of a 15 year olds, and it just keeps getting further and further crushed as we go down. I suppose that speaks to what you said earlier, which is one of the hallmarks of aging, is this sort of lack of resilience, and we see it on every level, but this is just a very notable example, which is even at the level of the autonomic nervous system, we lose the ability to recover from insult. And life is an insult. Everything in life is an insult. The world around us is insulting us all the time.

Joel Jameson
It's just we can respond much better to it as we're younger. Yeah. Do you have a sense, by the way, of what it is physiologically at the cellular level that is resulting in this profound reduction in HRV as we age? They've looked at this, and I don't know that we have a great answer for the exact physiological mechanism. We know it's tied to mitochondrial density, mitochondrial function.

We know it's tied to elements of the immune system. We know it's tied to hormonal status. And we obviously see decreases in all those things as we age. You just have to wonder which ones are causal and which ones are the response. I don't think we know that, but we definitely know that we can increase our age of e or we can at least prevent the decline most effectively through cardiovascular fitness.

We see people with higher vo two s have higher mitochondrial function. They have higher vo two that leads to or at least correlates with greater HRV. So we know that cardiovascular fitness in general seems to be the most closely tied to average HIV. Theres also a pretty strong genetic component which we cant ignore. Can talk about that.

But, yeah, if you look at the hallmarks of aging paper, which im sure youve seen, they kind of take these buckets of things, right. They say, oh, as you age, you get dysbiosis, you get deregulated nutrient sensing, you get senescent cells, you get stem cell exhaustion, you get myocardial. They list all these things that happen as we age and they kind of look at this prism of whats the output? And if you read that, they say, okay, the output, two of the major things are loss of resilience to homeostasis and lack of a stress response that's appropriate given the world around us. So, yeah, where that cause and effect and which one's causing the other is tricky to say.

But I think fundamentally aging is this progressive loss of adaptability. And there's multiple pieces to that, obviously. But we're measuring that, as you mentioned, is one of the things that we want to gauge of HRV is how much of that resilience of that adaptability are we losing as we age. And that's something we can influence through lifestyle and training and everything else that were trying to do here to prevent that slowdown. One of the things in that AMA that I didnt get a great answer to was how much genetics played a role on this, but from our patient population, because even though thats not a huge n, weve got years and years of seeing these data in patients where every single one of them is using some sort of device, by the way, it's even devices we haven't talked about, like if you look at really high end things like mattress covers and things like that, like the eight sleep will now measure that quite accurately from every form of wearable and out, you've got endless streams of data.

Joel Jamison
And there's an unmistakable difference between people. There are some people who, and let's just talk about this in RMSSD. We should talk about the other numbers because you have to do this. Apples to apples. But if we just talk RMSSD, I've got patients who live at 100 and a good day for them, a good day for them, quote unquote, they're at 120 and a bad day for them, they're at 85, but if you follow them for five years, their average HRV is going to be 100 milliseconds.

I've got other patients whose average HRV is 15 milliseconds, and a good day for them is 25 to 30 and a bad day for them is ten. How could that be explained by something other than genes? It isn't. I mean, I've looked at a bunch of this research just to understand, and it's all over the map. Depending on what paper you're looking at, depending on which metrics they calculated, they say genetics is somewhere between like 15 and 70 something percent of HRV.

Joel Jameson
There's just such a wide range in the research of what you see, where that exact number falls, I'm not sure, but you definitely see a very strong genetic component to it. Why? I don't think we truly understand that. But as you mentioned, I see people who don't work out at all and they come into the gym or they whatever, and you look at their numbers and you're like, you have a very high HRV that you would not expect because you clearly don't have a very high level of cardiovascular fitness. But ill say as a whole, if you start talking to those people, they tend to have a healthier family history, they tend to have better health markers.

I think theres something to that. And that higher HIV probably still correlates to a health benefit, even if it doesnt necessarily come from exercise derived means its just a genetic thing that they have that probably confers some benefit. Would you put HRV in a comparable bucket to Vo two max in terms of the following amount of it that is genetically determined, amount of it that is modifiable, and the role it might play in understanding overall health status. So for Vo two Max, I know the answers to all those questions. Right.

Joel Jamison
There is a genetic component. It's not huge. It's probably closer to that 15% than 70%. It's highly modifiable but difficult. And the fact that it's highly modifiable but difficult to modify is why I believe it is.

And youve probably heard me say this, the single greatest predictor we have of mortality. And if theres a better one out there, id like to hear it, but I havent seen one. And I think thats because I always talk about Vo two max as the integrator of so much hard work. You cant cram for the test if your Vo two max is in the top 1%, you werent born there. You blood, sweat and tears your way to that, and all that work does so much good for you.

Okay, so let's use that framework to evaluate HRV. How genetic is it, how modifiable is it, and are the modifications you have to put into it, then speak to, hey, if somebody improves their HRV by 50%, how confident are we that that moves the needle in terms of what actually matters, which is not the silly number, but actually the outcome of their life? No, I think it's more genetically based just from what I've seen, and probably a bit less modifiable. I would say it's less predictive in the sense that if I have somebody who's got an HRV of 110, to use your example or whatever, and then I have someone who's got a vo two max, I know is, I don't know, 70, I can pretty well know that person with a vo two max of 70 is pretty aerobically fit and they've lived a pretty solid lifestyle and had done the work and the training to get that level. I'm more confident that that person's longevity be fitted and affected from that.

Joel Jameson
That I'm confident than somebody who has no workout history that just has a high hrV. I dont know that I could say the same confidence at all. Just because they have a higher hrV, that they would have the same protagonistic value in all cause mortality. So its a metric that we arent gauging output from. Were just measuring this internal physiological state, and I think that confers benefits to someone who has higher HRV.

But I cant necessarily just look in that number instantly, say, oh, this persons really healthy or this persons really fit necessarily, because you do see that much stronger genetic component. Now, if I see a coupling, if I see some of the higher vo two, and I see higher hrV, chances are that's a reflective of all the things we just talked about, a healthy lifestyle and a lot of hard training, and the physiological changes that come as a result of that, and we're more confident that those numbers are going to line up with all cause mortality. So a nice way to interpret that, Joel, would be the as much as people are worrying about their HRV, and people really do worry about it, you should worry more about your vo two max because you have more control over it and it's a better predictor of all cause mortality, I think that what gets measured gets managed. Right. And because HRV is so ubiquitous and it's so spit out, and basically you're at the point now where if you go get a Starbucks.

Joel Jamison
They'll tell you your HRV, that they've somehow inferred from the pressure your lips put on the cup. I'm being facetious. Everybody is inundated with these data and it is creating a lot of stress. Yeah, I think we want to look at output measures. Vo two max is the best output measure.

Joel Jameson
We can look at something like heart rate and zone two heart rate recovery. Heart rate recovery. We can look at actual output measures because at the end of the day, I fundamentally think that's what matters. As we age, we need to be able to continue to move, and we need to be able to continue to be able to respond to our environment around us. And output is where we can see those metrics.

What's the metabolic cost for us to move around? If we can maintain movement as we age, we can be highly active. If you look at people that you know around you that are healthy and older, a lot of them, they're very active. They move around, they have hobbies, they have friends, they're social, they do things they love, and that's a big part of keeping them healthy and resilient. If we don't have the metabolic capacity to move, we've decline a lot faster.

And so again, vo two max and heart rate at different speeds. That correlates the ability to move and maintain that as we age. That's far more predictive, I think, than just an internal metric that is important but does not have the same predictive power. Do you have kids? I don't.

Joel Jamison
So anybody who's got kids, especially young kids, will appreciate this comment, but I've become so much more cognizant of a metric I would love to introduce to the world that ties into what you're describing called spontaneous movement. And Im an old guy, and even though Im fit for my age, I dont waste a lot of movement. So Im already at that stage in my life where I actually think of myself as quite lazy. So I love to exercise, and obviously Im not lazy when Im doing that, but if Im walking through the airport, Im just walking. I will use the stairs and not the escalator and all that stuff.

I get it all. But if youre with my kids and my two boys are six and nine, the amount of spontaneous, explosive movement is something I don't remember doing as a kid, although I'm sure I did it, too. But it's really a remarkable thing. And we also have a puppy, so we have this puppy that also is bouncing off walls. But when you see older dogs, that's done.

A 14 year old dog is not. Even if it's in good health for its age, it's not bouncing off the walls, whereas that puppy can't stop moving. And the same thing, like, when I look at my boys, like, everywhere we go, they have to race. Everything is a race. They're sprinting there.

And so if we're walking somewhere, they're doing sprints to and from us the whole time. I just think, a, there's something beautiful about that, and. But I think it speaks to this idea of youth. Youth is about movement. It is converting the chemical energy of our food into the electrical energy that powers muscles.

And spontaneous locomotion seems to be this. So I don't know, at some point, like, I would love to know, like, is there a way to take that as another output metric which gps on somebody? Exactly. Like, what is the drive to spontaneously move for no apparent good reason. We talk about we lose hrv, right?

Joel Jameson
But we also lose sympathetic drive too. We lose some of that ability to turn that sympathetic dial up as we get older, too. And probably it's as we've lost both of those capabilities. The ability to turn that symptomatic dial up and crank out more energy and produce adrenaline and cortisol. Is that what you think explains the fall in maximum heart rate?

Part of it is loss of contractility of the heart, loss of contractility the muscular system, loss of hormonal release as a result of the sympathetics. I mean, you're just losing, again, this adaptability, this ability to turn those two dials as necessary to meet whatever demand your place in the body. We can't turn that sympathetic dial up as much. We don't have that spontaneous energy that you just described to get up and sprint, because that dial is way slower, and it probably can't go up as high. Yeah.

Joel Jamison
So it's like we were born with a zero to ten rheostat or dial on both of them. And as you age, that ten goes to a 98765, and you can still move them, but you just can't move them as much. Yeah, 100%, I would call autonomic range. And that really kind of represents what is our body capable of from an energetic standpoint. How quickly can we turn that dial up?

Joel Jameson
And then, conversely, how quickly can we turn that dial back down and crank up that parasympathetic side to restore homeostasis and get our bodies back to normal? It's interesting, if you look at, I've looked at the paper where they looked at different navy divers that were going through this qualification school, which is kind of their equivalent of seal training and hell week and all that, and they tried to pick out what are the variables that separate the people that are really good at this and succeed and make it through versus the ones that dont. And they measured HRV throughout the process. And essentially they find what I just talked about is this autonomic range where they could really crank up the sympathetic system when they needed to, and then turn it off as soon as the stressor is over and respond in the other direction with a much higher parasympathetic response. That ability to use those dials quickly and in the right combination seems to be a really key thing to get adaptability.

And as we said, if you age, if both those dials lose their range and they lose their coordination in some specific, then we have much less resilience, much less adaptability. And we should mention too, as you pointed out, the Vegas and the sympathetics, they do influence behavior in a lot of ways. There's a whole thing that's outside my lane in the psychosocial aspect of this. And you can look at the polyvagal theory by Stephen Porges. But fundamentally, the brain regulates emotion through autonomic function in some capacity.

And the vagus is related to social behaviors, it's related to cognitive control in different scenarios. It's related to all sorts of stuff. They call it fight, flight, freeze. All these things related to how our autonomic nervous system is influencing our emotions. And if we don't have that autonomic range, we probably have less drive to get up and move around as a result of that, as those nerves in the autonomic system changes what it can.

Joel Jamison
And can't do, I don't think that should ever be underestimated or understated. I think, again, just even looking at a sample size as small as our patient population, I think we see that a lot. I think theres a very clear association between an individual that if you just look at them from a movement and exercise perspective, has a very difficult time relaxing and relaxing sounds like such a silly word, but I mean that in a sort of a clinical sense, if they cant let their rib cage down, if they cant properly generate intra abdominal pressure, if they cant go through a sequence of movements that generate some amount of motor control and compensatory relaxation, contraction, I think there seems to be very high association between that and emotional stress and psychological stress, 100% and actually pain as well. So I think we see chronic pain and again, you could argue, well, where's the chicken? Where's the egg?

If you're in pain, does that lead to more emotional stress? Does that lead to an inability to regulate relaxation within the body, which further exacerbates pain? It's a very vicious cycle. And you see lack of sleep. Older people need just as much sleep, but they have a harder time getting as much sleep.

Joel Jameson
And sleep is very much tied to that vagus nerve and the parasympathetic nervous system. So again, if we get worse quality sleep, we get less adaptability. It is chicken and egg. But fundamentally, that's why we want to regulate ourselves correctly. And that's where exercise.

I think the biggest thing exercise does is improves our bias ability to regulate itself. It improves the use of those dials because we are exposing the body to aerobic training that we know has some broad correlation to that. And were giving the body a stress it can adapt to in a positive way if we do it in the right amounts. And thats the caveat there. Before we leave the measurement thing, I want to go on to another one or two of those measurement at Morpheus.

Joel Jamison
What do you guys use to measure? So we use RMSSD and then we use log natural transform and a multiplier. That sounds like a lot of math, but essentially, if you look at the data of RMSSD and you look at like a normal bell curve, its skewed, its non normal all the way to the left. So you get these normal ranges of 20 to 80 or 100, like you said. But then you can get an elite athletes 100 and 8200 and see this big bunch of data on the far left hand side.

Joel Jameson
It's kind of hard to intu for it. So again, I'm not a statistician. I didn't create the formula. But essentially to normalize this data and make it look more naturally distributed, more like a normal bell curve. You do this log natural transform, use the multiplier, and Morpheus ends up on a scale that looks more like 100 point scale.

So people with lower HRV, more like the 50 60 people with more moderate 60 70, higher 70 80 elite athletes are going to be 90 to 100. It's more of a scale that we have a more familiar relationship with, I would say. And the data is more normalized from a standpoint of a bell curve. So it's just an easier to interpret. But that's the reason for it.

Joel Jamison
So do most people when they start using Morpheus and they're also using whatever other device they're using. That's just a purely RMSSD device. How much discordance are they typically seeing between them? It really depends on what they're using. It can be a big difference between the device that they're using, the numbers they're getting, but the trends should generally line up.

Joel Jameson
If you're seeing Morpheus increase as a whole, you should see the other one increase as a whole. You should see the directional change matching. But the actual numbers will be somewhat different depending on where you're at in that spectrum. Let's now talk a little bit about Morpheus. I've alluded to it a couple of times.

Joel Jamison
So it's a product I've been using for about a year and a half, maybe close to two years. But before I talk about my experience with it and why I use it, everything I do, I do for a reason. I'm a very deliberate human being. So there's a very particular use case that is pretty narrow for how I use it. I know that I'm not using it to its full potential, but tell folks what this is about, your involvement in this, and that's obviously how we got to know each other.

Joel Jameson
Yeah, I mean, when I started using the old system, I had to wait for people to come in the gym to measure them. And so I realized I was getting a pretty small snapshot of what their life story was because I might measure them two or three times a week. Sometimes they come in the morning, sometimes they come in the afternoon. And I realized the limitations of that. This is back in 2007 or zero eight.

And so I wanted to create something that people could use their phones and that we could get way more data from. And that was my first system, Bioforce HRV 2011. And that was really one of the earliest HRV apps out there where we could take your phone, you could do a recording, and you could get your HRV on your own, you didn't need to to come into the gym. And one of the limitations of that was all I could look at was your HRV. I didn't necessarily have any idea what else was being tied to that.

And so I could look at the change and ask you a bunch of questions and maybe try to figure out what those changes were coming from. But I wanted to create something that also tied in training and sleep and subjective markers and other metrics so that as a coach, I just had a more complete story of what was happening. And so that was really the genesis of Morpheus. And I started that in 20, 2016, 2017. So quite a few years ago.

And basically what we're doing is we're measuring HRV, and then we're tracking activity, sleep, workouts, all that sort of stuff. You can use the Morpheus device for a lot of that, or you can use other devices. So if you're using an Apple Watch to track your activity, your sleep, or Garmin, we'll pull that data in. But what we're trying to do is take that HRV. This is something we should definitely talk about.

There's a lot of apps that give you HRV, and then you can either say, okay, I'm going to interpret what this means myself, and I can try to figure out what these changes are. It's a physiological metric, or you can say, the apps are giving me a recovery or a readiness or some gauge that's based on that. Now, this comes back to every apps doing this completely differently, where we have a lack of standardization across not just the HRV measurement, but then how that information is interpreted to generate recovery or readiness, or some sort of number that the person in the app is saying, oh, my recovery is 80%, or my readiness is, these are just numbers that we are creating as a way to try to interpret the data. And then some of those apps, I think, do a reasonable job with it. Some of them dont.

But I created Morpheus, and this idea of the recovery score based on what I had seen using HRV for 20 years, or maybe 15 years at that point, its just a metric of whats appropriate for you on a given day. What is your body more likely to benefit from? And so we should probably talk about, again, what is recovery? What is readiness? Because those are metrics that Morpheus gives you and Ura gives you, and whoop gives you, and Garmin gives you.

Like a body battery, or every kind of app has their own gauge of that. But then the question is, how accurate is it? What does it really mean? And I think that's where a lot of confusion also comes in, because we're trying to take metrics and turn them into something that's not a physiological measure, but something we try to create. Yeah, I mean, look, I used an oura ring for many years.

Joel Jamison
Probably haven't used it in a year, a year and a half. There's better devices I can use to track my sleep now. And the recovery score, as you said, even if you believe the score is accurate, and there's no reason to believe it necessarily is, more importantly, it's not something you can act on. Let's just say you believe the number and you say, okay, my recovery score is 80. Today, I certainly believe that if it spits out a 90 versus a 70, your whoop or aura, theres probably a difference there.

Youre probably better off on the day youre 90 than the day youre 60. But how do you operationalize that information? And so when I was introduced to Morpheus, it was actually someone on my clinical team that said were having a hard time giving people real instruction around zone two because most people dont want to do what you do, Peter. Nobody wants to check their lactate levels and go through this. And I get it.

I never fault somebody for not wanting to do a finger stick every time they do a workout. And truthfully, for some people, just relying on RPE can be challenging. So this person said, hey, look, the Morpheus app, and we'll talk about how it works. I also appreciate how the measurement is taken. The Morpheus app gives you target zones for heart rate every day.

And if you use the cutoff between what it's calling zone one and zone two, that's a pretty good proxy for what your zone two is on that day. So I bought the system and started using it. And I should show you the data, because I have recorded every single workout I have ever done for the last year and a half, and I record the following. I record the heart rate predicted by Morpheus for what my zone two is, the heart rate I largely end up at by RPE. And sometimes they're close.

Usually they're quite close. Sometimes they're quite far. So sometimes Morpheus tells me to be at 138, but I'm kind of gassed out at 131. And sometimes it's the reverse. Sometimes Morpheus says, you should be at 133.

But I feel fantastic, and I go to 140. What the power was for the interval and what the lactate is. And I have to tell you, Joel, I cannot put in words how impressed I am with that system and how remarkably accurate it is at predicting something that is very difficult to predict. So kudos to you for doing that. What I find amazing are the days when.

And I had one of these days a week ago, Morpheus said I should have been at 140 or 139 for zone two. I got on the bike, and I did not feel great. And I sort of said, I think Morpheus got it wrong. I'm going to ride to this wattage. And my heart rate was about 132.

And I checked my lactate, and it was 1.1 millimole. I was nowhere near my limit of where I could have been that day. Now, again, we could get in the weeds on maybe that's fine. Maybe that's all I needed that day. And maybe I should have just been following how I felt.

But if I'm really trying to get the right training effect, I was under training a little bit on that day. So I'll kind of pause there because I want to kind of let you sort of interpret what I'm saying. And why is it about that? Because you spit out three zones. Zone one, zone two, zone three.

And I think you call them recovery and conditioning. Yeah, it's just terminology, right? It's just a way to gauge low, moderate, high intensity, more or less. Does it surprise you? Because I haven't told you this story before.

In all of our communications, we've never talked about this particular issue. Does it surprise you that the heart rate that is on the cusp between your first and second training zones happens to correspond to this lactate of two sweet spots? I mean, that was really the intent when I designed it. And that's, I think, probably that's difference in Morpheus, I would say, is when I designed it, it was as my experience as a coach for many years of testing lactate of Vo two max testing of HRV testing, I took synthesize a lot of information that I gained and a lot of knowledge and insight I gained to create this structured system of low, moderate, high intensity. You can call them whatever you want to call them.

Joel Jameson
That's basically what the zones are. And the biggest thing I realized is, as people's autonomic nervous system changes intensity and heart put our heart rate changes. And you learn this over time. When you see today, a 140 is doing this and tomorrow, 140 might be doing that based on changes in the autonomic nervous system. And so, when I created the algorithm, it was just based on a lot of data collected over a number of years of what I'd seen in the gym, what I'd measured.

Would I then look back at the data? And so that was the end result of Morpheus was trying to translate changes internally with how we can then turn that into smarter, more accurate and precise training. And that's what you're seeing with Morpheus. So it's awesome to hear that it's that accurate for you and some people, it's always going to be much more accurate than others. But as a whole, Morpheus is by far the best way to translate, again, changes internally with changes we should be doing in the gym.

Joel Jamison
Yeah, I mean, basically for our patients now, we almost never bother with them checking lactate. It's basically RPE. If you can manage it if you really have a sense of what zone two feels like. Great. But if you want some guidance, look, take the mafatone formula, 180 minus your age.

Great place to start once youre getting a little more nuanced. If you want more guidance, use morpheus and go to that heart rate again. Tell folks how I get that number every morning. How is it spitting out that number? For me, its.

I have to do a measurement, right? Yeah, I mean, you have to measure your hrv. And then were looking at other things that youve done in the past 24 hours, if youre recording it, and then based on your fitness level. So we ascertain your fitness level by looking at your resting heart rates, by looking at your average hrv, by looking at some of your heart rate trends when you're training. And we say, okay, Peters.

Joel Jameson
Roughly, at this level of fitness, Peters autonomic nervous system is responding in this way, which again, correlates to how its going to react today. If Im fatigued, then its going to take more energy to produce the same level of power output. And then we estimate, like you said, what for you is this cutoff between low intensity, moderate intensity, and high intensity? And a way that people can think about this, I would say, is muscle fiber recruitment. So low intensity is primarily slow twitch muscle fibers doing the majority of the work.

And specifically, if zone two, we're talking about where they're mostly oxidizing fat as much as possible, kind of this moderate intensity, we're starting to recruit some of those moderate threshold fibers. And we can talk about what that means, but we're starting to recruit some of those faster twitch, higher threshold muscle fibers and then higher intensity. We're starting to really recruit all the muscle fibers and the highest intensity muscle fibers. And so as Morpheus is looking at this, it's basically saying, okay, roughly this heart rate, we think this is the level of intensity that is going to correspond to these low, medium, and high. And then it's giving the ability to just plug in Morpheus and say, I want to do zone two.

Morpheus says, okay, based on what we've seen, this is where we think your zone two is for you today. And zones the same thing. Yeah. And again, I just want to reiterate, this is why it's very valuable. It's actually giving me the prescription every single day.

Joel Jamison
When I got it, I was a little surprised. I sort of bite at sight unseen. I was just told it's valuable, but I didn't understand the nuance. So the thing shows up and I realized oh, every morning I need to do a two and a half minute lay down in bed before I get up, still test measuring my heart rate and I guess you can do that. Morpheus at the time came with a chest strap and an armband.

I think now it's just a chest strap. So you put the chest strap on in bed, you lay there, you answer a couple of questions. So it wants to know how many hours did I sleep the night before. So I pull that data off my sleep tracker, my eight sleep whats the quality of my sleep? Im pulling off that as well.

And then I think its saying how sore am I subjectively and how good do I feel? Yep, just subjective markers. Those are actually reasonably validated markers for training performance. They are. And then I measure, I lay there and just kind of do nothing, meditate usually and it measures my hrv and heart rate and then it spits out heres your hrv, heres your heart rate, heres your basically your recovery score as a percent.

And then here are your target training zones which then come up again when you train that day its already loaded into the app. So your training zones change every day. So one of the things that surprised me Joel, was like wait a minute, im used to having to measure hrv over the course of a night. What is the difference between what my aura ring used to tell me by measuring over 8 hours of sleep versus this thing that's telling me in two and a half minutes in the morning before I've gotten up? This is probably the most important part of HIV because there is so much confusion on this.

Joel Jameson
If we look back historically, all the data that's been used, these all cause mortality studies and all the different pieces of literature out there, 95% of them are from spot HIV measurements that we are measuring at a specific time. And you're doing this in standardized conditions as much as you can to get a baseline because we want to know where is your autonomic nervous system? Same time every day. Same time every day, the same conditions. Because what I want to know is last 24 hours you did something yesterday, you did lots of things.

I assume you ate food, you maybe worked out, you maybe had alcohol or maybe you didn't. You did mental stress or maybe you didn't. You put your body in a situation where it had to respond for the majority of the day to do something and then you went to bed. And we want to see the result of that. We want to see this stress and recovery cycle that you went through yesterday because that tells us where your body is at right now.

How is it responding? Because, well, look at changes over time and understand how your body is adapting to the world around you. And that's what most HRV has been built on, is we measure in standard conditions. We see where you're at today, and that informs us about what happened over the last 24 hours and maybe slightly beyond. And the analogy is, if I was going to weigh myself, I'd want to weigh myself first thing in the morning in standard conditions.

I wouldn't want to have a meal and then go weigh myself. I'd want to have very standard ways of measuring so I can see the changes, because ultimately it's you changing against yourself that's the most informative. So we wake up, we measure HIV, we see where you are, and we see where you were, what your averages have been, what your variations have been, and that tells us where you are today. And that helps us make a decision about what are you ready to do right now, or what's the most appropriate for you to do right now. One thing I'll say is if your HRV is high or low, we can talk about what those mean.

It doesn't mean that you can't train hard. It just might mean that, like, that might not be the most beneficial thing for you, and there might be a cost associated with that. If I wake up, my HRV is way outside of normal. You can't say, oh, I can't work out today. You can.

It's just a question of, is that what your body needs? Yeah. To be clear, I don't think I've. I mean, I don't think I have never once not exercised as a result of what that said. And there have been days when I've had abysmal scores, and it's told me, like, my heart rate range on what it has told me is never above about 141.

Joel Jamison
There have been days it's been as low as 121, which for me means, like, my recovery was 35 or 40%. That's a night when I didn't sleep and something was dramatically off. You'd still do the workout. You're still the workout, right. You just are aware of what the cost of that workout will be.

Joel Jameson
You might make adjustments tomorrow or through your plan. That's what we're getting when we're measuring at the end of sleep, the morning time, we're seeing what was the result of our sleep, what was the result of our workout. So yesterday, everything else we did, if we're measuring HRV overnight, HRV number one is always higher at night because the parasympathetic system is. That dial is already turned up quite a bit because you're sleeping where it's the highest. Although for most people, Joel, they will see the reverse.

Joel Jamison
Like my RM SSD. HRV overnight is lower than the log normal transform I get out of Morpheus. Yeah. Cause Morpheus, if you look at the actual RMS d data, you would see that you'd be hired. And I know Morpheus is different obviously.

And can we see that in the app? You can't right now. Honestly, when we first came out with Bioforce and Morpheus, there weren't so many other apps to compare against. So it wasn't as big a deal to not show the raw number. So we chose not to.

Joel Jameson
But now I think we probably will just because people do want to compare. But anyway, overnight that dial of that parasympathetic system was already higher. So we're getting less of a responsiveness to see what actually is changing at rest. We're not measuring at rest. The second thing is if you have arrhythmias, if youre an athlete who has very high HRV, you dont have as much variability.

Were not really gauging the true responsiveness of the 24 hours before. Were measuring more of what to doing during the recovery. Doctor Justin during the recovery period, which has some correlation obviously, but were not really seeing where are you at the end of that recovery period? Where are you ready to go today for this next period of stress? And heres the biggest thing is if you do something, if you do a workout in the evening, if you have a few glasses of wine, if youre doing something very mentally challenging the first part of your sleep, youre just responding to that.

And so your HRV is not reflective of this whole process. Its just reflective of hey, you just did an evening workout and your HRV is still suppressed for the first half your sleep responding to that workout. So we dont get a true picture of where am I at right now and how does that correlate to what I should be doing for the next twelve to 18 hours as im awake across the next day? So I think were just probably getting a much better gauge of sleep and how our body respond during sleep. But we're not really getting this true picture of how did our body go through the whole process of life, sleep recover next, we don't see that picture as well because we're not measuring at the end of sleep.

We're getting this average across it. So I don't think it's telling us really the same thing, and it doesn't have the same utility for telling us from workout perspective, what's the most appropriate thing for us to do? Might be a silly question, but it occurred to me now, as we were talking about this, the one fundamental difference from one day to another in that morning check for me is there are some mornings I wake up and I have to pee so badly, and there are some mornings when I don't. And there's a part of me that's wondering as I'm laying there doing my test while needing to pee, is that putting a little more sympathetic tone into this? Am I getting a skewed measurement?

Joel Jamison
Would I be better off going peeing, coming back, waiting a few minutes? I'd go to the bathroom, get up. It's not that big of an issue. If you just go up, go to the bathroom, you come back and you reestablish. And part of that is actually measuring how well can you reestablish that?

Joel Jameson
If that's significant, impacted your HRV, it probably was on a lower end to begin with, but that does bring up a point I should mention. People with really high HRV is. I don't think this becomes an issue, at least in Morpheus, until you're in the nineties or resting heart rates. In the low to mid forties, your HIV is already very, very high. That laying down, you're taking some of the responsiveness away.

If you start getting to those categories, you probably want to take it seated. The challenge for most people seated, they get antsy, they move around, you introduce more motion artifacts. It becomes more difficult. But we really want to have as much range that dial available as possible because we want to see how the nervous system is turning that dial. So if you're very high, like I said, I would say someone who's resting heart rates.

Joel Jamison
Yeah, I'm never above the low. Eighties is as high as I get. Yeah, I think at that point, laying down is still a good way to take it. But if you get up in the nineties, mid nineties, you really want to maximize that potential responsiveness. And that's where a seated measurement makes more sense.

Joel Jameson
But that's a fairly small percentage of the population that's going to be up in that ranges. RMSD. You're talking one hundred and twenty s. One hundred and thirty s. One hundred and fifty.

We get up in those ranges, you probably want to take it seated. Okay. When I bought the Morpheus a couple of years ago, you had an armband and a chest strap that came with it. So I still use the armband as my morning check. That way I don't have to move them back and forth.

Joel Jamison
It always sits right there and then I use my chest strap when I'm exercising. You've gone to just a chest strap. Is that because you think you're going to get better data and it's just better to have people using the chest strap for both? And should I do the same? I mean, it's two things.

Joel Jameson
I don't think the data, as long as you're measuring consistently and you have the chest or you have the armband placed correctly and that's not any less accurate, I don't think the problem we ran into is people, as you know, are trying to use our armband to train because it's more convenient. Like, oh, the armband is goes my wrist. And their workout data was just not as accurate. The second thing is it looked like a watch, but it wasn't a watch. And so we had a bunch of.

Joel Jamison
Confusion with people putting it on their. Wrist, people putting their wrist and not sure what to do with it. It just created a lot of confusion. So at the end of the day, I said, look, look, the chest strap is giving us the best data is unambiguous if people really want to wear an arm vise device because they just don't want to put the chest strap on. We work with the rhythm, the Scotch rhythm 24, because it uses the exact same sensor that Morpheus used in our original armband that you have.

Joel Jameson
And so if they want to do that, they can measure it that way. But from a accuracy perspective, from both the HRV and the workout, it just made sense for us to standardize that, use the chest strap and make it as universal as possible, rather than trying to sell two devices which people were ultimately somewhat unsure of. Preston okay, so lets talk a little bit about the question that Im sure is on everybodys mind, which is ive been doing this for a while and I get that at the individual for my data, I see my up and down level and I know that hey, when its higher, im generally going to perform better and I can push a little harder. When its lower, Im probably not going to perform as well and maybe need to make that a little bit more of a less hard day. But then you get this question of, hey, what can I be doing to improve the quality of my health in a way that is measured by this output of HRV?

Sure. I mean, this is where HIV is driven by genetics. Fitness, primarily cardiovascular fitness, is the biggest thing. We see Corleone drive it, and then obviously, lifestyle, doing things in your lifestyle that make that sympathetic dial come down when you don't need it, and doing things that turn on that parasympathetic dial when you're not using this is going to put you in your highest level of your particular range from a lifestyle perspective. And that's where I think most people underestimate the lifestyle impact on HRV and train everything else.

They don't realize if you're stressed out from work 6810 hours a day, you're running around chasing your kids, you're doing all these things in your daily life that has a pretty significant impact on your HRV, because that sympathetic dial will be turned up for hours on end. Maybe not the same degree, of course, as a workout, but hours on end. So a lot of it comes down to just the stuff we know in everyday life that makes us healthier. Eating healthier foods, making sure we're getting enough sleep, managing our mental stress effectively, doing things that allow us to relax and turn that parasympathetic dial back up and that sympathetic dial back down, and then build vo two max. So do you think it's more impacted by peak aerobic fitness or by base aerobic fitness?

Joel Jamison
Would you say it's more impacted by higher zone two or a higher vo two maximum? I mean, they both contribute exactly how much, you know, I couldn't say. We tend to measure aerobic fitness from a peak standpoint for the most part. So that's more standardized what we would look at. But I think training frequency matters, which is where you get zone two.

Joel Jameson
Right. You can't do Vo two max training five, six days a week. We do a lot more zone two. We do a lot more frequency and volume of that, and I think that translates more than likely into a higher HRV, even if you didn't go out and do a bunch of the zone two or the Vo two max type work. Yeah.

Joel Jamison
And then one of the advantages, I think, of those overnight tests, again, whether it's aura, whoop, eight, sleep, any of these things, is people have noticed how much of an impact alcohol has on overnight HRv. It's probably one of the most profound changes you see in response to alcohol. And I would argue that a big part of the movement we're seeing around people drinking less can be attributed to those devices, which is giving people visibility into, oh, my God. Like, I didnt realize that alcohol could have such a profound impact on this. I guess that would kind of be out of your system.

Maybe the next day, or would that still be there in the morning? It would depend in the sense that if you had alcohol close enough to bedtime, it could impact your sleep, which impacts your recovery, which will impact the morning measurements. Youll still see some remnants of it, for sure. But, yeah, youll see that more directly in the overnight stuff. I think as a whole, what we see is people become much more aware of things like alcohol, things like excessive stimulants or, God forbid, smoking or massive amounts of chronic mental stress.

Joel Jameson
Those things impact much more than I think people realize. Example of this, we were measuring a college soccer team across a couple of seasons, and we would see that during finals week, they would look far worse than during tournaments, even competitive playoffs, just because that stress of being in a finals week where you're studying and you're not sleeping and you're stressed out, give. Me a sense of the range that you would see. Give me an average athlete where this would be their morning HRV under these circumstances. This is what it looks like when they're overtrained.

Joel Jamison
This is what it looks like when they're in the tournament. This is what it looks like in finals. Yeah. Again, there's a lot of variability there. But from a college standpoint, most soccer athletes that we would see, these are female athletes to be in the low mid eighties on a normal basis.

Joel Jameson
And this, again, this is Morpheus system. That's, you can't compare these to other numbers, but they'd be in the low to mid eighties kind of as a normal range. We shouldn't drop into the seventies, sometimes down fifties, which is in Morpheus. That's the stress. Yeah, that was the stress of finals week.

It's two, three, four days of not getting much sleep and studying a lot and just working out very less or very sporadically, probably compared to normal training sessions. You just see the impacts of life being very, very significant, that people don't necessarily expect that because they feel like, oh, the workout's the most impactful thing. Well, it is in a way, but it's also only an hour, maybe 2 hours. It's the rest of your life that also adds up to a huge amount of stress. If you are very, very stressed and if you're going through your life life in that kind of type a, I'm always turned on.

I can't turn off my stress. That has a very big impact. I think Sapolsky, who I know you've had on the show, talks a lot about the mechanisms. Like, you see that play out pretty frequently when you look at HIV data. I don't utilize the Morpheus system fully because I only wear it during my zone two workouts.

Joel Jamison
So I don't wear it when I'm doing my vo two max workouts because I'm already wearing that polar system. Cause it pairs with the garmin and it pairs with the other power meters and all the other stuff I'm using. I guess I could double up. Can you wear two chest straps? I mean, you could.

Joel Jameson
The polar should be able to connect to the Morpheus app directly while you're training, but then it would have to. Pair to two apps. It should be able to. If it's got two Bluetooth radios, which it probably does, you probably could do that. That would be good to know.

Joel Jamison
But I don't wear it when I'm strength training. So I realize that I'm failing to give it all of the data. Cause that's another. I don't wear it when I'm rucking. There's a lot of time.

I'm active, but I'm not wearing it. So how much am I missing out on in terms of the fidelity of what it might be telling me? Because I want to talk about the algorithm. One of the things you and I spend so much time on is I can't make sense of how it's coming up with the numbers, even though they end up being right most of the time. The more data you give it, obviously, the better it's going to be.

Joel Jameson
Exactly how much you're losing, and it's hard to say, but we're measuring the output with that hrv change and with the numbers that you're putting into it. We know the output of where you are. We can't always ascertain how you got there if we don't have. Have all that data, the workout sort of things. But as long as we have that consistent HIV measurement every morning in standardized conditions, you know, we're still able to get the vast majority of what we're trying to get, which is what are you most likely to do when you work out right now?

How much is that going to impact you? So that is the most important thing. That's by far the most important thing. To make sure that every day you see my heart rate, my heart rate variability, how long I slept, how sore I am, and my desire to train. Yeah, that's the vast majority of it.

Because again, it's telling us where you are right now. The readout. State the readout. That's the output. We know the output.

This is where your body is at right now. If we can reverse engineer that from the input, we can have some more insight into that. But you're not losing a bunch of accuracy because you didn't get that. We want the output. We want that as standardized and accurate as possible.

So I would say as long as you're measuring consistently every morning, the same context, same conditions, it's going to be more than accurate enough for what you want to do. Okay, great. And again, my use case is quite simple, which is mostly just predicting that zone two. But I have a feeling a lot of people listening to us will immediately resonate with that use case because I think for many people, there's still a little bit of ambiguity on not the concept of what zone two feels like, but the day to day variation, which. Again, is really significant, that speaks to the body's dynamic.

We can do a zone two tests and look at lactate and all these things. If we just take one test, we don't realize how much the body changes on a daily basis. And so if you just, okay, I took my lactate test six months ago. Im just using the static zone two. Youre missing that dynamic change that the bodys going through on a daily basis.

The body is not static. I measure blood pressure. I measure testosterone. Like all these numbers change constantly. The body doesnt sit still.

Joel Jamison
And I want to make another point, which is people again, might be listening and saying, peter, man, its too much data, dude. Just go out there and do it. Ill give you the counterargument to that. When I was a competitive athlete and I was training 28 hours a week, I had the luxury of junk miles. I didn't always have to be perfect, but I'm not a competitive athlete.

I'm a competitive father. I'm running three businesses. Like, I don't have the time for nonsense. Every minute I'm training, I have to get the training stimulus right, or at least as close to right as possible. So when I'm setting out to do zone two, I got to do it.

And if Im out there trucking along and my lactate is 1.1 or 2.9, Im missing the training effect I want. So the more insight I can get to narrow that down, the better. Im only going to give 3 hours a week or 4 hours a week to that training. Im not going to put 12 hours into it. Where if I do 12 hours and I screw up three of them, who cares?

I still got nine. So thats why I know that there are people watching this saying, dude, youre a psycho. And its like, like, no, I'm just efficient with my time and I don't want to waste my time. I think what it comes down to is each person has a certain amount of training in a week. I think it's a weekly basis because that's kind of the cycle we live in.

Joel Jameson
There's an amount and a type and an intensity of training that you are individually going to respond the best to. And if you go above it, not so great things are going to happen. If you go below it, you're not going to get the output that you want and that amount is not easy to find and it changes on a weekly basis. It's not the same week in, week out. And so the more that you can hone in on that core, how much volume do I need and how much intensity do I need?

If you can get that right week in and week out, you will see continual improvements and that work will turn into result. If you dont answer that correctly, bad things happen. You either waste your time because youre not getting as much out of as you could, or you do end up overtrained, in which case we see injuries and we see burnout and lots of things that are going to have negative health consequences. So I think ultimately what you said is I want to use information to make sure that Im getting the most bang for my buck. The best result for the amount of work I'm putting in.

And that's where I think data can play a really powerful role, is it's information that you can use to make much more granular decisions around rather than just guessing. Oh, I should go do 40 minutes today. Should you? Or I should do 200 minutes this week. Is there anything to support that other than just throwing stuff at the wall and seeing what sticks?

And I think that's what intrigued me so much about HRV is it felt like I could open the black box and get some real answers other than like test train for eight weeks, remeasure, see what happened. I don't want to wait eight weeks. I don't want to potentially lose the gains I could have made across that time period. So for someone like yourself, that's again wanting to get as much out of their time as they possibly can. Yeah, data can play a really strong role in that because it can answer questions that can't be answered otherwise.

Joel Jamison
And I think it only gets more significant as we age 100%. When I was 40, my recovery capacity was so much greater than now. Nevermind 30, 20, that's obviously. But even the difference between 40 and 50 is significant. And I know there are a lot of people listening to us right now who can relate.

Theyre sort of like, hey, Im getting a little bit older. I dont feel as great as I did. Its a question of time and age, and I think the further we get along that the more this type of system for me, I cant say enough about it. Age reduces your margin of error is what it comes down to. I mean, Im 44 and you can do a lot of things wrong in your twenties and maybe in thirties and you can still get a lot of benefit out of it because youre so resilient, your metabolism will adapt.

Joel Jameson
But like you said, the older you get, the less you can do that. And so you, you have to be much more acutely aware of what your body can and can't do. And that's part of what HIV can help you understand. You said something maybe 2030 minutes ago, and I jotted a note down because I didn't want to derail us at the time. I'll come back to it now.

Joel Jamison
So when I'm doing my Vo two max sets, the thing I monitor for every set is heart rate recovery. So as soon as I get to the top, because I do those on a hill, so as soon as I get to the top of the hill, I hit the lap timer and I count how many beats does my heart rate go down in the first 60 seconds at the completion of the interval. And that's a great proxy for how I'm doing. So I've got kind of my normal range should be 30 to 35 on a really good day. I'm 40 to 45.

A week ago or so, I had like one of the worst days I've ever had where I was like 19 to 21 in a minute. Thats all I could recover. I was smoked. Now I didnt sleep the night before. I made an Instagram post about it because I thought it was just a great sort of illustrative teaching point.

You said something that made me wonder about another test. Would there be any utility in right after a Vo two max interval, doing a heart rate variability test to see how much sympathetic tone can I dial down and how much parasympathetic tone can I dial up after what's probably a peak, you know, a very high sympathetic, low parasympathetic exercise? You can do that actually. I mean, it's very specific. Like, you can't move around if you want to get some standardization to it.

Joel Jameson
So yeah, you could do a 1015 minutes recovery period. What if I just did it right at the top, would that be too much? Probably. I think heart rate recovery is far better. It's.

Well, it's illustrative of what you wanted to get to, because what we see is heart rate recovery is driven by what the reactivation, the balance of those two, turning the sympathetic down as quickly as possible, and turning the vegas, the parasympathetic, up as fast as possible. So heart rate recovery is already giving you that information without having to get as granular as pulling out the b two b. You don't necessarily have to get that level of detail. You can just see the heart rate drop, and that drop is being caused by the increase in heart rate variability. And what's really fascinating is they used to think, and this is pretty new research I was going through, we used to have this idea that when your heart rate increased above 100 beats per minute, that there was really no vagus input, there was almost no parasympathetic.

And they figured that because they would look at acetylcholine as essentially they could block it into the heart, and theyd say, oh, we block acetylcholine from Vegas. And heart still pumps just fine during exercise. Exercise must not be vagusly driven at all. But what they found is that the vagus might actually be turned up a bit during exercise in some sense, because it can increase coronary blood flow by increasing vasodilation in the coronary artery. And so hiv is probably not the Vegas, I should say, is probably not completely inactive, probably not completely off.

It's this ratio. It could be turned up, but the synthetic system is turned up so much more, and it's using a different mechanism. We don't see the heart rate variability pie, obviously, but it's probably more ready to turn that back up even further. As soon as that sympathetic system starts turning down, and we're dropping our adrenergic hormone levels, or catecholamines, all these things are dropping pretty quickly. And the faster we can turn that parasympathetic up, the faster heart rate comes down.

The other thing that's interesting is they've looked at heart rate recovery in terms of, it represents, to some extent, the balance of the aerobic and anaerobic systems that contributed to that exercise. So the more aerobically driven something was, the faster a heart rate drops, because in a lot of ways, higher heart rates are driven by that sympathetic and by the anaerobic pieces of metabolism. So what do you see in young, exceptional athletes? I mean, I wish I had tracked this metric when I was a teenager, like, I wish I know how much my heart rate recovered then and back when my peak heart rate was 205 to 210. What do you see in these young collegiate athletes?

I mean, a really good number is 50, 60 from a near max. So I trained combat athletes, UFC fighters, priority fighters for many, many years, and they have to go into the octagon or cage ring, depending on what they're doing. And they have to fight for three five minute rounds, up to five five minute rounds, probably the ten minute round, which is crazy. So we would use heart rate recovery between rounds as a really good gauge. Because it's 1 minute between rounds.

Yes, exactly. And they would sit down between rounds, so we could standardize that. And so I would use that drop as a very good gauge of how well conditioned is this athlete, how ready to go out there. Give me an example of what you would see on a fighter. They would come out of the previous.

Round at what they come out, 100 6180, depending. I mean, it could be. Depends what the round is like, right? And the round was slower, it's going to be much lower. But most of the rounds are between like 100 6180.

Paying on their, their age or anything else. You might see them spike up and. They could drop by 50 to 60. I would want them to get to 130s between each round. We'd simulate this in sparring rounds, getting leading up to the fight.

We wouldn't measure during a fight, obviously, but if they're doing a simulated fight round where it's three fives or five fives, I want them to be able to drop in the 130s between every round. If we started seeing their first round, they weren't coming down below 100 5160. They're not in good enough shape. They're not good enough shape. They were going to fatigue every time.

And that just told us they were having to rely so much on the anaerobic piece. They were going to fatigue because at a sport like this, you have to be really explosive, but you have to also have the endurance. It's about the ratio of energy utilization that matters so much. If you don't have enough anaerobic, you're gonna lack power and speed and ability to finish. But if you have not enough aerobic, you're not gonna sustain that explosive power for very long.

And so it's really tricky to get that ratio right. And you see the fastest, most explosive, hardest hitting athletes often fatigue the fastest, because they're generating that from the anaerobic side, and they're relying on that, and that's great if they can win and they can knock the person out or submit them, but if they can't and you get in the later rounds, that's where they're going to really struggle versus somebody else who's more aerobically dominant. So that's a really hard part about that sport, is getting that ratio correct and training the right side of it. But the heart rate recovery was such a great way to see that. And so, like I said, I would want to see in sparring at least, you know, there are going to be higher heart rates during competition from the psychological stress.

But we want to see them drop in 130s again, this is seated going from standing to seated, but they should be able to get a heart rate back in the 130s between each round, ideally before they go for a fight. If they could do that and they were fighting high level pace, you knew they were in pretty good condition and they'd be ready to go out and go if they weren't doing that, especially if they're early rounds. If they're, like I said, round one, they're at 100 5160. You know, they better finish the fight quickly. They're going to be in trouble.

Joel Jamison
So, interesting. I want to go back to kind of what we were talking about on the trailing average of HRV data. So I'm glad to hear that my failure to utilize Morpheus in every moment of the day isn't really impeding its fidelity. I kind of know that because, again, as I said, it just. It's so damn accurate in what it predicts.

It's like a shaman. But what amazes me, you have the patience of a Saint Joel, because I email you so much. It must be infuriating. But what amazes me is how sometimes the data I see, I don't believe it. You're always like, yep, but you got to look back at what it did seven days ago and six days ago and five days ago.

And so walk me through the arc of HRV over time and how the undulation of the HRV matters as much as the HRV on a given day. This is the part that is totally news to me. And again, I think the proof is in the pudding, because at least for me, this seems to really work. Sure. Yeah.

Joel Jameson
I mean, again, we're looking at not just what is your number, but what is your number in relation to where you're usually at. And we're looking at how much does our number move today versus what's like a normal movement for you and again, were looking at just this manipulation of dials by the autonomic nervous system. So what morphs is doing is looking at your seven days and seeing, okay, whats your normal baseline number itself, but also whats your normal level of variability across those different time periods? And then we look at standard deviation. And so if we see big changes greater than one standard deviation away from your average, away from your baseline, we know that thats the odd number in your system responding to a greater input.

Its responding to more stress, and its having to make bigger dial adjustments. And that tells us that you've been paying a higher cost because you put your body under more stress. And if we were to probably illustrate, to just isolate, our body's in kind of a normal rested state, let's say, and then we do a single workout and we allow it whatever necessary time it needs to recover. During the workout, obviously, the body turns up that sympathetic dial, it turns down that parasympathetic dial. We produce more force, more energy, more power, blah, blah, blah.

And then after the workout, like we talked about, the sympathetic system starts to come down, the parasympathetic starts to come back up. Now, depending on the workout you did, that could happen in very different time scales. And Steven Seiler, again, a really popularized polar train, he was just showing some stuff. If you do like zone two and below aerobic work, that recovery happens pretty quickly. Within a few hours, we'll see that parasympathetic system turn on and it'll come up, up above your baseline to maybe 110, 120% of what your HIV was at rest.

So, Morpheus, you know, if you were, I don't know, a 70. If you were to theoretically remeasure it, you might be a 74, 75. You would see a noticeable uptick above baseline because our body has been able to shift very quickly into that restorative phase by that vagus nerve, firing more forcefully and turning up the parasympathetic. So we see, again suppression during the workout and the curve starting to come back up, up during lower intensity workouts, well see it pretty quickly come up above baseline and then kind of as your body went through that complete cycle and restored homeostasis and did what it wanted to do it, then it just kind of settled back down to where it started. And so you'd see this curve, this very clear curve now in a much.

Joel Jamison
Higher intensity, but the amplitudes aren't as big. Amplitudes aren't as big, exactly. In a much higher intensity, higher volume, even lower intensity, it's easier to be 3 hours of in heat. That's a much bigger stress. You see the same curve, but it would play out over a much longer time scale because it would take much longer for the body to restore back to where it was and then to get everything where you started with from a HIV standpoint.

Joel Jameson
So we'd see a much bigger depression, a much lower drop, and then we'd see a much longer time scale for it to come back up to normal. And then we might see it come up above normal for some period and then restore. But I'll say there's a big difference in the individual as well. People with higher HRV and people that are more fit, they're more likely to see this increase above baseline. Somebody who has less autonomic range, they can't quite turn that parachymph dial up as much.

They might never get up above baseline. They might just kind of spend time getting back to that baseline HRV. And you never really see the peak above baseline and then they're restored afterwards. So it's an individual thing based on fitness, but we should generally see suppression of HRV, an increase of HRV, and then kind of a back to normal HRV. And it's that process.

Now the tricky thing comes is we have so many other things influence it. It. Alcohol influences it, mental stress influences it, sleep influences it. So it's overlapping influences that will get to where you're seeing. But that's the core thing of our body response to stress by dropping HIV and then by recovering HIV and then by coming back to whatever that normal range is.

Joel Jamison
Yeah, and that's why again, I think it's not intuitive enough to just look at the HRV that given day. You can't just say my HRV was x today. And there's a one to one map between what my HRV is on a given day and what my training output should be that day. Because you need to know the first derivative, the second derivative, and frankly, even the arc that it's on, it's an all cause metric. That's not just looking at one input, it's looking at everything.

Joel Jameson
And so interpreting that output is not always the easiest thing in the world. And again, if you kind of look at this like, oh, up is always one thing and down it's always one thing. It's a little more nuanced than that because it's this responsiveness of, okay, it's going to drop after pure stress, then it's going to come back up. It might come up way above baseline and then kind of drop back down to normal. This curve is not always the most intuitive thing to understand.

And thats part of the challenge, I think, with people just kind of looking at it and say, oh, its this, im going to go do that. Yeah, I mean, its certainly not intuitive to me, which is why I annoy the hell out of you and pepper you with all these questions. Im going to change gears to talk about something ive alluded to a couple of times in the past, which is a phenomenon that we see in patients taking this new class of drug. I mean, its not really a new class of drug. Its been around for a decade, but a class of drug that has gained a lot of popularity in the past, probably two to three years, which is the GLP one agonists and the dual agonists with Gip as well.

Joel Jamison
And again, we dont have an enormous and overwhelming body of evidence on this. You know, we dont have that many patients in our practice, and we frankly dont have that many that take it. But certainly over the past three years have to think weve seen two dozen patients on these drugs. And again, in all cases, we have of overnight information on heart rate and heart rate variability. The unambiguous sign that we see is that resting heart rate is going up, and it's going up an average of ten beats per minute, with a range of about eight to twelve.

This is unmistakable. It's not subtle. And when they come off the drug, usually within a month, it goes back to normal. For patients who do indeed go off the drug, we're also seeing a compression of heart rate variability. So we see heart rate variability come down, although that's less predictive.

But I now realize we're kind of using the standard. We're not using like a morpheus, we're using kind of their oura ring or whatever. And maybe those data just aren't as accurate. My first question for you is, if there's something going on in a drug that is predictably driving heart rate up, would you expect it is also driving heart rate variability down? Do those tend to move in that?

Joel Jameson
Generally speaking? Yeah, generally speaking, you'd see that. Now, just as you mentioned that my thought would be, it's a strong appetite suppressant. Correct. The Vegas is very tied to appetite.

So if you think about this, if we were to turn up that sympathetic dial, our hunger gets turned down. We don't really want to be hungry while we're in the middle of some stressor, right. But after that period of stressor is over, theoretically, we've burned energy we need to restore and eat. And so the vagus is very connected to the gut and to hunger centers, and it feeds up into medulla, and it's controlled hypothalamus. There's a very strong vagal relationship to hunger and a desire to eat.

So I almost wonder if suppressing the vagus and decreasing HRV and increasing heart rate is a byproduct of how this is inhibiting appetite. That would make sense. And so it's an interesting question, because it then leads to another question, which is, if I told you that I'm going to change you in a way that your heart rate is ten beats higher when your HRV is ten milliseconds lower, you would say, well, whatever you did was negative. Sure, there's a cost to that, right? Do we think that that could be the case here?

Joel Jamison
I mean, again, we're really wildly speculating. You know, I get asked all the time, Peter, are these drugs safe? Are these drugs good? What do you think of them? And I'm always say sort of the same thing, which is look clearly, for some people, whatever unknown exists around these drugs is worth it.

If an individual goes from being 250 pounds to 200 pounds and having a hemoglobin, a one c of 7% to 5.5%, that is so positive for them that I think it justifies whatever unknown exists around these drugs. If there's no other way they're going to achieve that benefit. But I'm really more interested in these marginal cases of people who don't have diabetes and want to lose 20 pounds, which, by the way, might not really matter in their overall health. It's cosmetic. And are they taking too big a risk?

That's kind of the question I'm interested in, and that's why I keep coming back to if it raises your heart rate that much and lowers your heart rate variability, are we picking up a signal that is just a niche representation of appetite suppression via the vagus nerve, or is it actually playing a role in the parasympathetic sympathetic dials? I would imagine it's got to be. I mean, to move it that large ten beats is a fairly significant amount. I can't imagine that's not having an actual effect on our ability to regulate ourselves effectively. We're probably in a more sympathetic state all the time, which is going to have a cost.

Joel Jameson
Now, if it's a few weeks or a month, maybe that cost is relatively small, I don't know. But if it's weeks or months, they're living on this drug, I would suspect there's a real cost to that. And to your point, if it's the benefit is they lose a bunch of weight and all their blood markers improve and we see health outcomes, maybe it's certainly worth that cost, but maybe somebody like you said, who cosmetically wants to lose weight and they have an easier time on the drug doing that. Is that a net benefit? I mean, its hard to say because we dont have long term studies on those drugs, but I would just kind of say in general that, yeah, if we see these noticeable decreases in HRV and these varied noticeable increases in heart rate, thats a real sign that the body is that autonomic nervous system is being adjusted in an artificial way.

And that probably is not a good thing in the long run, specifically if its for a long time. Doctor Justin yeah. I dont know where the companies are at in terms of their post surveillance, meaning post marketing surveillance studies, and if this is a metric that they're tracking or interested in. But again, given the popularity of these drugs, there's no shortage of opportunities to kind of measure these things. Yeah, it'd be interesting to see like also I'd be curious what happens when they come off?

Do we see a big rebound? Does their heart rate stay suppressed? How does it change? Our sample size is so small that I want to be very careful and note that everything I'm saying is it could be nothing, it could be that, that it's just a very small n and 25 people is not enough. But the thing is, in the 25 people, I've never seen an exception.

Joel Jamison
When you don't need statistics to measure things, you kind of need to pay a little closer attention to them. It's pretty hard to modulate appetite that significantly without suppressing the Vegas to some extent because it's so closely connected. But we do see everything come back to normal when people are off the drug. And I'm trying to remember, it's been a while since I've looked. I feel like it's within a month, maybe even less.

It might be within two weeks, everything is going to happen. The half life is pretty long on those, so it probably does take a few weeks to clear up. And I don't think I have enough insight to contrast the two most popular drugs, semaglutide and terzepatide. But again, I don't think these drugs are going anywhere and I would love to better understand this. My guess is there are a number of people on these drugs that might not be aware of this because either they're just not tracking it or they are, but they haven't noticed it.

Some patients will say this after a few months, and I realize they kind of forgot when I told them this in the first place. But anyway, wondering if you had seen anything about that or heard anything about it. ADHD medications, for example. You see a very suppressed HIV and a very elevated sympathetic or resistant heart rate. You see in several types of things like that, any sort of strong stimulant.

Joel Jameson
Obviously, those are not stimulants, but people who live on caffeine and Red Bull and are constantly shoving coffee to constantly turn that sympathetic dial up is, to me, a kind of sign that the sympathetic system isn't working the way that it should by itself, probably because you've overstimulated to begin with through stress and lack of ability to turn that off. And we see people reach for stimulants and artificial ways of turning that sympathetic dial up once their body's not doing it the way that it should. And so we see people kind of self medicate with stimulants to get that sympathetic response when, if they had been able to manage stress more effectively, they probably would have a normal functioning sympathetic system that wouldn't need that artificial stimulus to turn it up. Let's take a step back, and now just talk about where you think HRV belongs in the hierarchy of health metrics. Weve talked about so many different types of health metrics, and weve talked about how output metrics tend to be preferable.

Joel Jamison
We can sort of think of them as functional metrics. I like an oral glucose tolerance test more than a hemoglobin. A one c one is kind of functional. It actually is a test. It watches how you do something.

Vo two max strength. Those are more functional tests than maybe resting heart rate or muscle mass. Muscle mass is great. It's predictive, as is resting heart rate. But when you actually put the work out, HRV is obviously a readout state.

Where do you think on the dashboard of health longevity? Where do you place it? You know, I think it's important to monitor as you're going along. But I would say if all your other metrics are telling you you're healthy and you're going the right direction, nine times out of ten we tell you the same thing. The point where I would be more aware of it is where it's very low and you don't have a reason for that.

Joel Jameson
You want to figure that out. We've had people have arithmetic as they had no idea about and they go to the doctor and they have some serious heart condition that they need to be aware of. But I would just say long term, it should line up with Vo two. It should line up with your metabolic market. It should line up with all of this stuff.

It's easier to track because we can measure it on a daily basis. I think that's probably the advantage I would say it has, is you're not getting a Vo two max tests every day, obviously, or every week, every month. You're not doing lactate tests, and you're not doing these markers that are more output based that are really important frequently enough to get feedback of whether or not you're going the right direction. So I think we can look at HRV in a more granular daily basis, just kind of say, am I going the right direction? And that's probably more of a utility than a great predictor of something.

And we can look at those daily changes to help us make more informed decisions. We can't do that with Vo two max or with more invasive tests. So it's a more narrow data point, but it gives us something we can use more actionably than these longer term tests, I think are better actual measures of outcome. And if we see our HIV trending down significantly, significantly, that is a warning sign we're doing something wrong. Our body is not adapting the way that it should be, and we need to make adjustments, whether it's training or lifestyle.

So I think it's used differently. We use Vo two and we use those sorts of output measures as are we going the right direction? And we have some prognostic value specifically from them. We use HIV to say, are we more likely to be making improvements in the short term or are we heading the wrong direction? Where if we keep doing that for long periods of time, we're going to either see the benefit or the cost direction we're going.

So I think they're different. It. Is there a number, Joel, on the log normal transformation you're doing on the RMS SD, a number below which, if it's consistently there, I would want to inquire more. Fifties forties. I mean, those are pretty low numbers for a Morpheus user.

Joel Jamison
Again, just for folks listening, that's not the RMSSD number. The RMSSD number might be far, far lower than that. Yeah, exactly. Yeah. So you really do have to be specific of what we're talking about.

Joel Jameson
The system. This is an one. But I was at a guy. There was a guy named Mel Siff who you probably aren't familiar with, but he was a very well known sports scientist. He wrote a book called Supertrain.

I was at his house with the original HRV system I was using and had all the metrics, and his armist, he was like five, and he just looked really bad. Then he had a heart attack. And I said, mel, this looks really concerning. He was, you know, he kind of brushed it off and he died of a heart attack a few months later. And so, you know, if you're really seeing this super low arm SSD or Morpheus numbers, it's definitely an indication that that autonomic nervous system is not responding well to the world around it.

If it's really, really low, there could be a legitimate medical concern that's driving that. So if you're Morpheus, forties, thirties, and you're just not getting up, it's probably worth looking into, and it's something to definitely be concerned about. And do you see the opposite, where really high numbers or a sudden change from low to high can indicate an arrhythmia or something like that? Yeah, absolutely. You definitely do see these weird numbers come out.

That could be arrhythmia, that could be medications, it could be, who knows? You see some of these things jump around from anomalies that you just kind of like, that's artifact. I don't know what happened. And then sometimes you do see a medication or you see weird tech stuff with COVID and you definitely see some weird stuff in the data that you want to be aware of that you probably wouldn't pick up otherwise. I would say HIV is more of a leading indicator and kind of how you feel.

And some of those symptoms can come days later. So you'll oftentimes pick up something that looks weird, and then two days later you get a cold or you get flu or you get some sort of of thing that explained it. Good, good. Joel, this is awesome. I feel like I know much more about this now than even after I did the AMA a couple of years ago.

Joel Jamison
And I learned a lot to sort of prepare for that. So appreciate it. And again, I apologize, because on some level, this, for some of the listeners, probably sounds like a bit of a morpheus commercial at times. But obviously, I have no affiliation with Morpheus at all. But I point to it because, again, I'm a big consumer of data.

I test every device out there extensively, and I view it as the stickiest device I've ever found for this use case. And so I do hope that people check it out. I think I just bought it online. You buy it direct to consumer, right? I don't think you buy it on Amazon or whatever, so I would encourage people to, if they want to take this to another level that they should check out morpheus I appreciate the work you're doing, Joel.

The curiosity and inquisition with which you bring to this is fantastic. I benefit from it greatly and those are my patients who use it also as well. So thank you for both all the work you're doing and obviously coming here to talk about it. I appreciate being on here and be able to speak to your audience. I think the biggest thing I've learned after 20 plus years of coaching is we're all different.

Joel Jameson
And as much as it may be easy or attractive to say, oh, this is what somebody else is doing, let me just try that. Let me just do the same thing. If you can spend the time just copycatting someone else's workout and really dig into your own physiology, how you respond to training, how you respond to diet, how you respond to different food intakes, really learn how your physiology works, you will reap the reward to that in the long run. I think that's where tools like HRV and sleep monitors, they build awareness. And whether you're using Morpheus or Ura or whatever else, using that data to really be your own coach and really understand your own physiology and your own biology, that's the ultimate way to get better results and have the health outcomes you're looking for.

So I appreciate the opportunity to talk about that. Thanks, Joel. Thank you. Thank you for listening to this week's episode of the Drive. It's extremely important to me to provide all of this content without relying on paid ads to do this.

Peter Attia
Our work is made entirely possible by our members, and in return we offer exclusive member only content and benefits above and beyond what is available for free. So if you want to take your. Knowledge of this space to the next level, it's our goal to ensure members get back much more than the price of the subscription. Premium membership includes several benefits. First, comprehensive podcast show notes that detail every topic, paper, person and thing that we discuss in each episode.

And the word on the street is nobody's show notes rival hours. Second, monthly ask me anything or AMA episodes. These episodes are comprised of detailed responses to subscriber, typically focused on a single topic, and are designed to offer a great deal of clarity and detail on topics of special interest to our members. You'll also get access to the show. Notes for these episodes, of course.

Third, delivery of our premium newsletter, which is put together by our dedicated team of research analysts. This newsletter covers a wide range of topics related to longevity and provides much more detail than our free weekly newsletter. Fourth, access to our private podcast feed that provides you with access to every episode, including AMA's Sans, the spiel you're listening to now and in your regular podcast feed. Fifth, the QAlys, an additional member only podcast we put together that serves as a highlight reel featuring the best excerpts from previous episodes of the drive. This is a great way to catch up on previous episodes without having having to go back and listen to each one of them, and finally, other benefits that are added along the way.

If you want to learn more and access these member only benefits, you can head over to peterattiamd.com subscribe. You can also find me on YouTube, Instagram and Twitter, all with the handle Peter attiamd. You can also leave us review on Apple Podcasts or whatever podcast player you use. This podcast is for general informational purposes only and does not constitute the practice of medicine, nursing, or other professional healthcare services, including the giving of medical advice. No doctor patient relationship is formed.

The use of this information and the materials linked to this podcast is at the user's own risk. The content on this podcast is not intended to be a substitute for professional medical advice, diagnosis or treatment. Users should not disregard or delay an obtaining medical advice advice from any medical condition they have, and they should seek the assistance of their healthcare professionals for any such conditions. Finally, I take all conflicts of interest very seriously. For all of my disclosures and the companies I invest in or advise, please visit peteratiamd.com about where I keep an up to date and active list of all disclosures.

There.

#305 - Heart rate variability: how to measure, interpret, and utilize HRV for training and health optimization | Joel Jamieson

Primary Topic

Episode Summary

Main Takeaways

Episode Chapters

1. Introduction to HRV

2. Practical Applications of HRV

3. Technological Advances in HRV

Actionable Advice

About This Episode

People

Companies

Books

Guest Name(s):

Content Warnings:

Transcript