If our bodies are 98 degrees, why does it feel so hot outside?

This episode explores the science behind human body temperature and why external temperatures feel different despite being the same as our internal temperature.

1. Human bodies are constantly producing heat from internal activities like digestion and circulation.
2. Our bodies maintain a temperature of around 98.6 degrees Fahrenheit through homeostasis.
3. External heat feels oppressive because it disrupts the body's ability to expel excess internal heat.
4. Humidity worsens this effect by preventing sweat from evaporating, a key cooling process.
5. Understanding these mechanisms helps explain why different temperatures feel more extreme than the warmth inside us.

1. Introduction to Homeostasis

Explores how the human body maintains a constant temperature through various internal processes. Molly Bloom: "Your body is a hopping and very hot place. That's because all of these activities create heat. A lot of heat."

2. The Role of the Hypothalamus

Details the function of the hypothalamus in regulating body temperature and its effects on our physical state. Molly Bloom: "There's a part of your brain that helps with homeostasis by keeping track of your body temperature."

3. Challenges of Heat Regulation

Discusses how external temperatures above 70 degrees Fahrenheit affect the body's cooling mechanisms, particularly in humidity. Molly Bloom: "So as it gets hotter than 70 degrees outside, it becomes harder for our bodies to get rid of extra heat these ways."

• Stay hydrated to help your body sweat and regulate temperature.
• Wear breathable, light-colored clothing in hot weather to improve heat dissipation.
• Use fans or air conditioning to assist in removing body heat in extreme temperatures.
• Limit physical exertion during the hottest parts of the day to reduce heat production.
• Monitor humidity levels; use dehumidifiers if necessary to aid in sweat evaporation.

98.6 degrees is hot. If it were that hot outside, you’d be sweaty and want to go jump in a nice cold pool. But the insides of our bodies are that hot all the time! And that’s because there’s a lot going on in there that creates heat.

People

Molly Bloom, Sattvic

Content Warnings:

None

Amy Poehler
This is Amy Poehler. My new movie, Disney and Pixar's inside out two is coming to theaters June 14, and it's making me feel joy and sadness and anger. Definitely some disgust rose and I think a little fear, really. But I'm also feeling these new emotions like anxiety, embarrassment, envy, and ennui. It's what you call the boredom.

Okay, that one was weird. It's gonna be the feel everything movie of the summer. Disney and Pixar is inside out, too, only in theaters June 14. Get tickets now.

Gengar
Hello, it's me, Gengar, and I love blazon universe. Support it. And me, Gangur, by doing two things. First, dance, dance, dance.

And second. Go to brainson.org donate. Thank you.

Sattvic
You're listening to Brainson, where we're serious about being curious. Brainson is supported in part by a grant from the National Science foundation. Is this thing on?

Frog
Greetings, brains on, listener. It is I, a frog. I noticed this episode of brains on is all about body temperature, specifically, how the human body is always around 98 degrees. To that, I say, seriously, the same all the time. How boring.

It's like only dancing to Charleston all your life. Ha cha chi chittity cha chi chi chi cha. Another attempting tap. Tippity tippity tippity tippity tap, hey. Orally singing operatic style la dee da da and never scatting.

Beebe dee dabbity dabbity ba. As a frog, I don't keep my body at one single temperature. I am the temperature of my surroundings. Sometimes I'm hot. Sometimes I'm cool.

Same with other amphibians, reptiles, insects and fish. And have you noticed humans are always eating because they need so much energy to keep their bodies warm? Excuse me. I use my thumbs to open this banana and use these giant teeth to mash them up into spaghetti. Num num.

Do you see me doing that? A flick of my tongue, and there's a delicious fly in my belly. Once again, it goes to show that humans are the infuria animals and frogs. We've got the upper leg. And another thing.

Oop. I hear one of the humans coming. Excuse me. Oh, there you are, Roger. Ribbit.

How did you get out of your tank and into the studio? Back under the heat lamp you go.

Molly Bloom
You're listening to brains on from APM Studios. I'm Molly Bloom, and my co host today is Sattvic from Danville, California. Hi, Sattvic. Hey, Molly. Now, here's a little behind the scenes into how Brainzon gets made.

We get hundreds of questions from listeners every month. We read them all. It's so fun. And then we choose a number of these questions to answer. And that's how we pick our episode topics.

Since we get so many questions, sometimes it takes a while to get to the episodes we want to do, and this one took longer than most. Sattvic wrote to us six years ago when he was eight, with an excellent question. Yeah, I was curious about human body temperature. I wanted to know if the average normal temperature inside the human body is 98.6 degrees fahrenheit, then why don't we feel hot the same way we do when it's 98 degrees outside? It is such a good question.

If 98 degrees is normal inside our bodies, why does it feel so hot when it's 98 degrees outside? It's been on our list of possible topics for a long time, but we never got to it until this year. So I reached out to Satvik. He's 14, and lucky for us, is still curious about this topic. I still want an answer.

So, Satvik, what makes you curious about the human body and the way we regulate our body temperature now? Because my parents are both doctors, I've always been curious about biology. And when I came up with this question and asked them, they thought that we should have reached out to you. That is very cool. Thank you for doing that.

Sorry it took so long. If you could choose between feeling very hot, like being somewhere where it's super hot outside, or being somewhere where it's super cold, what would you choose? I feel like I'm pretty adapted to both extremes because where my school is, we're at the base of Mount Diablo, so in the morning it's always freezing. But then I still live in California, so in those summers, it's always hot. But I think if I really had to choose, I'd go with always being hot.

Why is that, do you think? I don't know. I feel like I have a lot more experience being hot than being cold. And what are your favorite ways to cope when it's hot out? For the most part, I do indulge in ice cream and popsicles sometimes, but what I really like to do is just carry around a massive water bottle filled with ice water and refill it constantly.

And I know that you're still really interested in science. What kind of science are you most excited about? Well, before I was really interested in biology and zoology, but because six whole years have passed, my scientific interests have changed a lot. And right now I'm more interested in physics and math. What got you interested in physics and math?

Sattvic
I don't know. I think it was something about math being the building block of all of science and physics being the closest thing to math. Well, before we get to the heart of your original question, let's figure out why our bodies are so hot in the first place. 98.6 degrees is hot. If it were that hot outside, you'd be sweaty and want to go jump in a nice, cold pool.

Molly Bloom
But the insides of our bodies are that hot all the time. And that's because there's a lot going on in there that creates heat. Your heart is pumping blood through your body. Your lungs are moving air in and out. Your stomach is digesting food cells.

Your body's tiny building blocks are turning that food into energy, and that helps them do what they need to do, like grow hair, heal, cuts, power your brain. And there's so much more going on in your organs and your bloodstream. Your body is a hopping and very hot place. That's because all of these activities create heat. A lot of heat.

Sattvic
So much heat that your body has to spend a lot of time getting rid of it in order to stay around 98 degrees. When your body is nice and balanced and running as it should, that's called homeostasis. It's a fancy word that just means everything in the body is working as it should. All's good. Homeostasis.

There's a part of your brain that helps with homeostasis by keeping track of your body temperature. It also makes sure your body is doing what it needs to do to stay cool. It's called the hypothalamus, and it's always working hard to help you do things like pump blood and sweat. I actually have a workout video for us to try by the hypothalamus herself. Let's sweat it out.

Hypothalamisti
Hi, I'm hypothalamisti the hypothalamus. And welcome to the homeostasize studio. I hope that body of yours is ready to move, because we are ready to beat the heat. Ooh, do you feel that? It's getting hot in here, so we better bust out our moves.

Just follow my simple step by step instructions, and you'll be sweating it out in no time. Let's start by getting that blood pumping to the skin. And pump, and pump. And pump and pump. And as the blood flows from the surface of your skin, it's able to dump some of that heat from inside the body.

Pump and dump. Pump and dump. Who cares if your face is a little red? That just means you're a master of the pump and dump. Ooh.

I can feel the heat radiating off your skin from here. Now it's time to get wet with sweat. Squeeze that sweat out. Secrete, secrete, secrete. And as that sweat dries and evaporates, it takes the heat with it.

Bye bye, heat secrete. Bye bye, heat secrete. Ooh. Very good. You're getting that heat out of your body like a pro.

Time for our last move. It's called the booty shake. You bend your knees just a little bit and shake that rump from side to side. Uh huh. Ooh.

Aha. Uh uh. Get down with the music. Ooh. Ooh.

Yeah. You're probably wondering, how does this get rid of heat from my body? The answer, it doesn't, but it's a great way to elevate your levels of funkiness. And that's all for today. You've done an amazing workout.

You've pumped and dumped. I saw you secrete to beat the heat, and now your body is just the right temperature. I'm the hypothalamus, and you're welcome in my homeostasis studio anytime. Time. Bye bye.

And don't forget to hydrate.

Molly Bloom
I am sweaty. Me too. That was a workout. So our body is able to dump some of the heat it makes by pumping more blood near the surface of our skin. That blood carries heat with it, and the air around our skin soaks up that extra heat, cooling us off.

Sattvic
We also lose heat by sweating. When little droplets of sweat evaporate from our skin, the water and some of the heat float off into the air. That cools us, too. Our bodies are able to do this best when the air is 70 degrees cooler than the insides of our bodies. Ah.

So as it gets hotter than 70 degrees outside, it becomes harder for our bodies to get rid of extra heat these ways. Yes, especially when it's humid. When air is humid, it means there's already a lot of water floating around in it. So it's harder for the water in our sweat to evaporate because the air already has plenty of water and it doesn't need more. So the usual techniques of cooling us off don't work as well when it's humid and hot, so we feel uncomfortably hot.

Hypothalamisti
Hi, I'm the hypothalamus, and welcome to the homeostasize studio. It's hot in here. Like, really hot. Okay, let's try our tried and true methods. Get that blood to the skin.

We'll pump and dump and pump and dump. I'm pumping. But the dumping isn't working so well. It's so hot. Okay, let's try sweating.

Secrete bye bye heat. Secrete bye bye heat. Oh, the sweat isn't evaporating. I'm so hot. Oh, you know what?

Molly Bloom
Forget it. I'm going to the pool.

So, when it's hot and humid outside, it's harder for our bodies to keep that homeostasis. And we feel hotter. The answer to my question. Finally. Bodies are 98.6 degrees because they produce a lot of heat.

Sattvic
But we need to constantly dump heat to feel cool. Yes, and if its 98 degrees outside, we cant dump heat very well. Were going to hear what happens in our bodies when our temperature goes above the normal. But first, something else for you to puzzle over. Its time for the.

Gengar
Mystery sound.

Molly Bloom
Sattvic. Are you ready for the mystery sound? I am. Wonderful. Here it is.

Hmm. What do you think? Well, I mean, it definitely sounds like something grinding, so I'd say a table sliding against a concrete floor. Ooh, a very good guess. Should we hear it again?

Sattvic
Sure. Okay, here it is.

Molly Bloom
Any new thoughts? I mean, it does seem to be going back and forth, so maybe two really rough rocks rubbing against each other. Ooh, very nice guess. I have no idea what this is either. Why do you think someone might be rubbing rocks against each other?

Sattvic
I have no idea. Maybe to grind them to a powder like a mortar and pestle. Ooh. Well, we're gonna hear it. Get another chance to guess and hear the answer after the credits.

Molly Bloom
So stick around, listeners. We love getting mail from you. Head to brainson.org contact to send us your mystery sounds, drawings, and questions like this one. Why does ice help with swelling? You can find answers to questions like these on the moment of, um, podcast.

A short dose of facts and fun every weekday. Again, that's brainson.org dot.

Frog
Brainson universe is a family of podcasts for kids and their adults. And since you're a fan of Brainson, we know you'll love the other shows in our universe. Come on, let's explore.

Hypothalamisti
Entering brainson universe. So many bad guests. Brains on smash. Boom. Best forever ago.

Picking up signal. Smash. Boom. Best a debate show. What are they arguing about this time?

Molly Bloom
Tomatoes versus potatoes. I was just remembering, in 1949, the Mister potato head went into production, a pivotal toy in a lot of people's childhood. And I was googling, right now, Mister Tomato head. And the first thing, the thing that comes up is, did you mean Mister potato head? Oh.

Hypothalamisti
Hilarious. Zorp signal down.

Molly Bloom
Need smash. Boom. Best no. Search for smash. Boom.

Frog
Best wherever you get your podcasts. This is Amy Poehler. My new movie. Disney and Pixar's inside out two is coming to theaters June 14, and it's making me feel joy and sadness and anger. Definitely some disgust rose and I think a little fear, really.

Amy Poehler
But I'm also feeling these new emotions like anxiety, embarrassment, envy, and en week. It's what you call the boredom. Okay, that one was weird. It's gonna be the feel everything movie of the summer. Disney and Pixar is inside out, too, only in theaters June 14.

Get tickets now.

Hi, I'm Mark Sanchez, brains on, resident taco lover and weird gadget inventor. Almost every brains on episode starts with you. You send us a question, and we build a show around your curiosity. But there's another way. You're at the heart of the brains on universe.

This is a public radio podcast, and you are the public. That means we rely on your donations to keep us going strong. Every donation makes a difference. Contribute any amount today@brainson.org. donate.

Molly Bloom
Brains on. You're listening to brains on. I'm Sattvic. And I'm Molly. So far, we've found that it's hot inside our bodies because they're really busy and make lots of heat naturally.

And we actually have to be dumping heat through our skin to stay at homeostasis. That nice 98.6 degrees. But even though we talk about 98.6 as a normal temperature, its really just an average sattvic. How would you describe what an average is? Well, to get the average, when you have a set of data points, you add up all of the values and divide by the number of points you have.

Oh, very good. That math knowledge is coming in very handy today. So that 98.6 number was first put out there by a german scientist named Karl Reinhold August Wunderlich. He published it in 1868. And in his report he said 37.

Sattvic
Degrees celsius, which is the same as 98.6 degrees fahrenheit, was the average temperature. He said he took multiple temperature readings from 25,000 patients. That is a lot of data. Yes, some were a little hotter than 98.6 and some were a little cooler, but 98.6 was the average. But several groups of scientists have been studying this more recently, and they found that our average temperature is now closer to 97.9 degrees.

Molly Bloom
And we need to point out that our body temperatures do change over the course of a day. Our bodies are coolest in the early morning and warmest in the late afternoon. There are also differences between male and female bodies, differences based on age and body size. There are a bunch of reasons that our average body temperature is different now than in 1868. One reason for this is that we have fewer infections now, thanks to a more sanitized world.

And our bodies are warmer when theyre fighting infections. Many of us move our bodies less overall than people used to, and we also have better medicines and better nutrition. So even though were a teeny bit cooler, were still warm enough to keep our bodies running smoothly.

But sometimes our bodies really want to warm up, climbing to 100, 101, or even higher. Thats what we call a fever. And it turns out they're super important to help us fight off germs.

Gengar
I am Joe Alcock. I am a professor of emergency medicine at the University of New Mexico. And I work in the ER there in a big urban hospital in Albuquerque. And I also do research. If a normal body temperature is thought to be about 98.6 degrees fahrenheit, a fever would be over 100 degrees fahrenheit.

The question is, why does that happen, and why did that evolve? Fever has evolved on the planet in a bunch of different kinds of creatures. It's not just us. If your dog or your cat gets sick, they will also have a higher body temperature than what is typical for them. And what's really amazing is that even cold blooded animals, they don't have a way of actually increasing their body temperature internally, but they can actually increase their body temperature by seeking out warmth.

So lizards that get sick with a bacteria, they'll actually go and sit in the sun, and they'll worm their body temperatures higher than what non sick lizards do. But even some animals without backbones do this, too. So there's a senegalese grasshopper that when it gets sick, it seeks out warmer places, and the body temperature of the grasshopper goes up. But honeybees, when they get sick in their colony, what they do is they will actually shiver their their wings. They don't fly.

They just engage their little wing muscles, and they they basically shiver. And that increases the temperature of the entire hive. There's something similar that happens in worms. There's something similar that happens in snails. Okay, so the last common ancestor of birds and lizards and people and worms is about 4 million years ago.

So that means that fevers have been around probably on this planet for about 4 million years, maybe even longer than that. So for fever to be so widespread in the animal kingdom, then that really is evidence that fevers might be doing something useful for the animals that show a higher body temperature. People are still doing some experiments to figure out exactly why this happens. But it turns out that when you are infected with something, and this could be a virus, or when a bacteria is causing an infection, to be a successful infection, the invader has to reproduce. So one bacterium has to become two has to become four.

But it turns out that when you increase the temperature, it makes it harder for bacteria to replicate, so it makes it harder for one to become two. From your point of view, when you have a bacterial infection, it can be good to have the temperature be a little hotter, because that makes life a little bit tougher for the bacteria. It also makes life a little bit tougher for you. But that's a price that you are willing to pay to get over an infection.

Molly Bloom
So next time you have a fever and you feel achy and lousy, just know that your body is doing something pretty amazing and pretty ancient to keep you healthy.

Our bodies are always making heat, but there's a part of our brain called the hypothalamus that keeps our body temperature right where it needs to be, around 97 or 98 degrees. Our body can get rid of heat by pumping our blood closer to the surface of our skin and by sweating. Our bodies like to be so warm because the heat keeps germs in check. And when we get sick, we get warmer to fight off the germs. This is a fever, and it turns.

Out lots of animals have evolved to get fevers, too. That's it for this episode of brains on. This episode was written by Molly Bloom and produced by Rosie Dupont. Our editors are Sandon Totten and Shayla Farzan. Fact checking by Katie Reuther.

We had engineering help from Michael Peterson and Derek Ramirez, with sound design by Rachel Brees. Original theme music by Mark Sanchez. We had production help from the rest of the brains on Universe team. Anna Goldfield, Nico Gonzalez Whistler, Ruby Guthrie. Lauren Humpert, Joshua Ray, Mark Sanchez, Charlotte Traver, Anna Wegel, and Aron Wol de Selassie.

Beth Perlman is our executive producer, and the executives in charge of APM Studios are Chandra Gavotti and Joanne Griffith. Special thanks to Shruti Khuturu Brainson is. A nonprofit public radio program. There are lots of ways to support the show. Subscribe to Brainson Universe on YouTube, where you can watch animated versions of some of your favorite episodes, or head to brainson.org dot.

Sattvic
While you're there, you can send us mystery sounds, drawings, and questions. Okay, Satvik, are you ready to listen to that mystery sound again? Ready as I'll ever be. Molly. Okay, here it is.

Molly Bloom
What are your new thoughts? I think I am going to stick with my mortar and pestle answer, but I'm also pretty unsure because it does sound a lot heavier than a mortar and pestle. Maybe it's a giant mortar and pestle used by bigfoot. Maybe. Maybe.

That's probably not right. I think you're probably closer than I am. Should we hear the answer? Sure. Okay, here it is.

Hi, my name is Miles, and I live in Atlantic Highlands, New Jersey. And that was the sound of me waxing my surfboard. Oh, my goodness. Waxing a surfboard. Have you ever waxed a surfboard before?

Sattvic
I have not. And never in a million years would I have thought of that. That is so tricky. Okay, so when you wax the surfboard, you have this hard piece of wax that you rub on the bottom of. So it's hard, almost like a rock.

Molly Bloom
And the surfboard itself is kind of bumpy and hard. And so that's making that noise. Pretty cool, huh? Yeah. You're in California.

Would you ever like to try surfing? I mean, maybe just so I can wax a surfboard. Exactly.

Now it's time for the brains honor roll. These are the incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings and high fives. Lydia from Bluff City, Tennessee. Patrick from Worthing, UK. Kaylee from Columbia, South Carolina.

Johnna from Louisville, Kentucky. Joanna from Gordon, Georgia. Kai, Avery and Devin from Florissant, Missouri. Maggie from Berthoud, Colorado. Sawyer and Rory from Cincinnati.

Lila from Phuket, Thailand. Anissa and Hazel from Ann Arbor, Michigan. Luca, Ellis and Vivienne from Medford, New Jersey. Esme from Nashville. Celia from St.

Louis. Emma from Fremont, California May from New Orleans, Carolina from Washington, DC McKay and Lincoln from Clearfield, Utah. Elias from Portland, Oregon. Jack from Helena, Montana. Stella and iris from Pennsylvania.

Zoe from Fort Mill, South Carolina. Jacob from Massachusetts. Nolan from the Netherlands Maxwell, Oliver, and aiden from Leonardtown, Maryland. Mary from Baltimore. Clara from Edmonton, Alberta.

Alice from Chelmsford, Massachusetts. Margo from Chicago. Iris from San Francisco. Ellie from Sunnyvale, California. Tsai and Crockett from Tacoma, Washington.

Lauren, Kate, Joseph, and Nicholas from Batesville, Indiana. Serena and Sophia from Hillsboro, Oregon. Nora, Brendan, and Charlie from Raleigh, Massachusetts. Tom from Canmore, Alberta. Harper from Colorado Springs.

Henry from Portland, Oregon. Carson from Houston, Texas. Gabriella from Lincoln, Rhode Island. Miles from Malvern, Pennsylvania. Hanan from Vancouver.

Sylvia and Penelope from Seattle. Noor, alia, Liliana and Elias from Jacksonville, Florida. Jenna from West Jordan, Utah. Remington from St. Augustine, Florida.

Nathaniel from Seattle. Samuel from Chappaquah, New York Jacob from Atlanta Leo from Seattle Nathan, Naomi and Nehemiah from Taipei, Taiwan Mateo and Leo from Philadelphia Ruth from Atlanta Archie from Cambridge, New Zealand Ben and Emmy from Reston, Virginia and Rhea from Maryland. Praise my roll.

Next week, we'll be back with an episode about how trees help cities. Thanks for listening. Kids are full of a million questions. Like what is bankruptcy? Why does it feel good to spend money?

I want to know what unions are and what they are for. You may not have all the answers, but we do. Million bazillion, a Webby winning podcast from marketplaces here to answer the awkward, complex, and sometimes surprising questions your kids have about money. Listen to million bazillion wherever you get your podcasts.

Gengar
Listen to million bazillion wherever you get your podcasts.