Cavan Images/Getty Images
Cavan Images/Getty Images
Think sweat is gross?
"It could have been so much worse," says Sarah Everts, the author of a new book called The Joy of Sweat, that is all about, you guessed it, the science of sweating.
Turns out human sweat our body's air conditioning system is really pretty tame on the "yuck" scale of animal cooling methods.
Dogs drool to stay cool, while vultures will poop on their legs and seals urinate on their feet, she says. When you think about what evolution could have bequeathed us, Everts says, "sweat is arguably a million times better."
In fact, Everts tells NPR's Short Wave, instead of thinking of sweat as gross, think of it as an "evolutionary marvel." She even calls it a human superpower and a highly efficient one at that. "We effectively dispatch water to our skin and, as it evaporates, it whisks heat away from our bodies," she says.
Everts points out in her book that this superpower enables humans to thrive and dominate across the globe. "Sweating allowed us to forage out in the sun without overheating, while our predators were relegated to the shade for survival," she writes, and for us to adapt to many new environments. "Like the (city) pigeon and desert dove, we're capable of surviving almost anywhere."
Short Wave's Rhitu Chatterjee talked to Everts about the incredible science of sweat, which includes facts most people don't know. Like get this: How much you sweat is affected by both nature and nurture. And did you know you can sweat in different colors? Yep, both are true.
Check out Everts' fascinating interview below. Don't have time to read it? No sweat! You can listen to it by clicking on the audio link above.
This interview has been edited for clarity and length:
In your book, you write that to sweat is human. How much someone sweats is sort of a mix of their genetics and also where they've grown up, right?
It's kind of interesting because these glands they're called eccrine glands you're born with all the eccrine glands that you'll ever have. But these glands don't become fully active until you are in your toddler years. And so in those very early years of your life, your body is kind of learning about the climate that you're in. And researchers are trying to figure out how much of the environment in which you spent your early years is ultimately going to affect how much you sweat as an adult.
That's the nurture part. But there's also a nature part. Some people and some families are just sweatier than others. And, perhaps you have more sweat glands than average. Most people have between 2 [million] and 5 million.
I got mine counted. I have 3 million! And there's also the flow rate, right. So some people are very efficient with their sweating and some, the floodgates just open right up. And so that's also possibly related to genetics but also possibly related to acclimatization and your body learning on the go.
I mean, athletes do this right. In preparing for the Olympics in a really hot place, they will try to train in very similar conditions so that their bodies learn to cool down efficiently in that kind of environment.
You write in the book that sweat contains so much more than water.
Oh, yeah! So this was the thing that really blew my mind. When you think about sweat, it took me a long time until I was writing this book to be like: Where is it really coming from? It's effectively the liquidy parts of blood, minus the big stuff like red blood cells and platelets and immune cells.
And so if you open up a body, you're very wet inside. Right. You have this thing called interstitial fluid that's keeping all your organs damp and moist. And that liquid is sourced from blood. And when your body gets the cool-down directive, then your sweat glands source sweat from that interstitial fluid. So literally anything that's in your blood that's small can percolate out.
So, evidence of my morning coffee comes out in my sweat. When I have a drink of gin and tonic on a hot day definitely the alcohol comes out. Evidence of the food we eat, evidence of our health or even how we're exercising.
There's a story that you write about in the book: the South African nurse whose sweat turned red.
Oh, to be this woman. She was a nurse and wore a white uniform and noticed that her sweat was red. And this is a very strange situation, right?
She was really insecure about it and went to a dermatologist. But they could not for the longest time figure out what was going on because she was in her 20s; she was perfectly healthy. They checked her for everything.
One day she comes to the clinic for a follow-up appointment, and one of the doctors notices her fingers are kind of stained like a reddish brown color. It turns out she had had a pre-appointment snack, and it was this corn chip called Spicy Tomato. She was very fond of these chips. She was eating multiple bags a day so very fond. The dermatologist called it a fetish.
They analyzed her sweat for the same colorants and dyes as the chips and got a match. And so effectively, once she dialed down her predilection for these particular chips, her red sweat disappeared. But other people have turned their sweat all sorts of colors for all sorts of reasons. It's a funny little corner of the medical literature called chromhidrosis: chrome, light colored and hidrosis for sweat.
What about the other components that sort of leak out into sweat? Do they have any role? And what makes sweat stinky?
What's coming out of your sweat pores the entire medical role for it, is to keep you cool. But in the process, your body also dispatches some proteins that do crowd control for the microbiome of your skin. Right. So helping the helpful bacteria thrive and trying to keep pathogens at bay. But most of the stuff that comes out in this watery sweat called eccrine sweat is just what happens to be flowing around your body.
Of course, there is another kind of sweat: The stuff that makes you really stinky. That's the sweat that comes out in your armpits. It's actually an entirely different kind of sweat gland. It's called the apocrine gland, and it gets active at puberty as many of us know.
And that one is not like salt water at all. It's kind of like waxy, a little bit similar to earwax, but a lot more minute, and the bacteria living in your armpits eat that sweat and metabolize it and effectively poop out what is the body odor that comes from your armpit.
So body odor changes, depending on the content of your sweat and the mix of bacteria that are metabolizing the sweat?
Exactly. And so we all have a unique body odor print, right? We all have our own smell. And that is effectively the mix of waxy molecules coming out of those apocrine glands, plus the unique-to-you ecosystem of bacteria living in your armpit. And so that combination is what gives you your unique odor print and mine. And allows dogs, for example, to track humans based on having sniffed something that they've worn.
You write that sweat is poorly understood by scientists. What are the things we still don't understand about sweating, and what are researchers investigating?
Some of the really interesting areas are the evolution of sweat glands and how we actually came to have evolved one of the most efficient ways to cool down in the animal kingdom.
We don't even know how many genes are involved in sweating. And a lot of other really fabulous research is still going on. [Researchers are] trying to, for example, do the forensics of science like monitoring what is coming out when we sweat and monitoring what are the chemical residues in a fingerprint. Because a fingerprint is just a sweat print. And forensic researchers are now able to learn all about your biological identity from the actual chemicals left behind in the fingerprint.
If you can analyze the chemicals of that fingerprint and find out, wow, that person was, you know, drinking alcohol or that person actually has cancer all sorts of very private information is being left behind in the drips we leave on our yoga mats but also literally on everything that we touch.
Read more here:
Sweat Is An Evolutionary Marvel Allowing Humans To Survive And Thrive : Shots - Health News - NPR
- Days of our Lives' Suzanne Rogers on the Evolution of Maggie: "She Knows Who She Is Now, and She's Not Relying ... - Michael Fairman TV - March 14th, 2024 [March 14th, 2024]
- Kylie Jenner Talks About Her Style Evolution - The Cut - March 14th, 2024 [March 14th, 2024]
- Equator Coffees Unveils New Packaging Design, Reflecting Brand Evolution & Vision For The Future - Sprudge - March 14th, 2024 [March 14th, 2024]
- Rosewood Hotel Group Accelerates Growth And Evolution Across Its Four Distinctive Brands - Hospitality Net - March 14th, 2024 [March 14th, 2024]
- Thomson Reuters Unveils New Brand Evolution - Adweek - March 14th, 2024 [March 14th, 2024]
- Is It Becoming Acceptable to Speak of Design? - Discovery Institute - March 14th, 2024 [March 14th, 2024]
- Did Charles Darwin Convert to Christianity and Discredit Evolution on His Deathbed? - Snopes.com - March 14th, 2024 [March 14th, 2024]
- Milk, it's not just for mammals: An amphibian makes it too - NPR - March 14th, 2024 [March 14th, 2024]
- Discover Puerto Rico Debuts Evolution of Its Successful 'Live Boricua' Brand Campaign Aimed at Engaging Visitors ... - Yahoo Finance - March 14th, 2024 [March 14th, 2024]
- A Journey Through Time: The Evolution of Ras Al Khaimah Art - Business Wire - March 14th, 2024 [March 14th, 2024]
- Empowering Women: The Evolution and Innovation of coto Social Platform - CXOToday.com - March 14th, 2024 [March 14th, 2024]
- The Evolution of Da'Vine Joy Randolph - The Root - March 14th, 2024 [March 14th, 2024]
- Study on mating behaviors offers clues into the evolution of attraction - Phys.org - March 14th, 2024 [March 14th, 2024]
- Dragonball Evolutions live-action Goku says goodbye to Toriyama: Sorry we messed up - AS USA - March 14th, 2024 [March 14th, 2024]
- Investec, evolution of SMEs in the materials handling sector - Leasing Life - March 14th, 2024 [March 14th, 2024]
- Pride & Prejudice and the evolution of the female gaze on screen - Yahoo News UK - March 6th, 2024 [March 6th, 2024]
- Joe Wong's Musical Evolution - Shepherd Express - March 6th, 2024 [March 6th, 2024]
- A global survey of prokaryotic genomes reveals the eco-evolutionary pressures driving horizontal gene transfer - Nature.com - March 6th, 2024 [March 6th, 2024]
- Redefining Intelligence: Chimpanzees Break Through the Cultural Evolution Barrier - Medriva - March 6th, 2024 [March 6th, 2024]
- Mollusk Eyes Reveal How Future Evolution Depends on the Past - Quanta Magazine - March 6th, 2024 [March 6th, 2024]
- Levy Delves Into the Evolution of ADCs in NSCLC - OncLive - March 6th, 2024 [March 6th, 2024]
- The Snake Is The Spearhead of Reptile Evolution, But Why? - ScienceAlert - March 6th, 2024 [March 6th, 2024]
- 'A very special day: Birds linked to Darwins theory of evolution reintroduced to Galapagos Islands - Euronews - March 6th, 2024 [March 6th, 2024]
- Why the Powerhouses of Cells Evolve Differently in Plants - College of Natural Sciences - March 6th, 2024 [March 6th, 2024]
- Driving the DevOps Evolution: ArgoCD, Tekton and Seamless Migrations - DevOps.com - March 6th, 2024 [March 6th, 2024]
- Finding the Balance: The Evolution of Public Health Guidance Amidst Controversy - Medriva - March 6th, 2024 [March 6th, 2024]
- Insider Podcast: Paolini dishes on her Polish roots and hard-court evolution - WTA Tennis - March 6th, 2024 [March 6th, 2024]
- Interview: Sara Gruen and Rick Elice Talk About the Inspiration and Evolution of the New Musical Water for Elephants - TheaterMania.com - March 6th, 2024 [March 6th, 2024]
- The Evolution of the Laravel Welcome Page - Laravel News - March 6th, 2024 [March 6th, 2024]
- A Serpentine 'Explosion' 125 Million Years Ago Primed Snakes for Rapid, Diverse Evolution - Smithsonian Magazine - March 6th, 2024 [March 6th, 2024]
- The Evolution of Modern Technologies in Car Development - FinSMEs - March 6th, 2024 [March 6th, 2024]
- Milwaukee Transformed: From Bronzeville to Veterans Park, Aerial Timelapses Reveal City's Evolution - BNN Breaking - March 6th, 2024 [March 6th, 2024]
- The eyes are a gateway to evolution of daddy longlegs at least. - University of Wisconsin-Madison - March 6th, 2024 [March 6th, 2024]
- Adrian Newey: RB20 is the next step in Red Bull's design evolution - PlanetSport - March 6th, 2024 [March 6th, 2024]
- LiveScore releases its 'Evolution of Fan' report - Gambling Insider - March 6th, 2024 [March 6th, 2024]
- The loyalty program evolution makes its way to the full-service restaurant category - Nation's Restaurant News - March 6th, 2024 [March 6th, 2024]
- Teenage Mutant Ninja Turtles: The Last Ronin II - Re-Evolution #1 spoiler-free review: goes hard on the action, but ... - Gamesradar - March 6th, 2024 [March 6th, 2024]
- Exploring U.S. Financial Evolution: DAR Hosts Talk on Federal Reserve History in Thomasville - BNN Breaking - March 6th, 2024 [March 6th, 2024]
- Why cloud evolution needs a cohesive approach to succeed - CIO - March 6th, 2024 [March 6th, 2024]
- Gilead Sciences CEO on Company's Evolution and Commitment to the Bay Area - BioSpace - March 6th, 2024 [March 6th, 2024]
- Navigating the AI Quandary: Human Supremacy vs Machine Intelligence Evolution - BNN Breaking - March 6th, 2024 [March 6th, 2024]
- Denis Villeneuve breaks down the evolution of sandworms in 'Dune: Part Two' - Mashable - March 6th, 2024 [March 6th, 2024]
- Continued evolution of law improves governing capacity - Chinadaily.com.cn - China Daily - March 6th, 2024 [March 6th, 2024]
- The Evolution of the DEX Space with dYdX's CEO Antonio Juliano - Blockster - March 6th, 2024 [March 6th, 2024]
- Quick Commerce Evolution: 3PL Firms Aim for Same Day Delivery, Chasing Blinkit and Zepto's Lead - BNN Breaking - March 6th, 2024 [March 6th, 2024]
- What If...? Star Jeffrey Wright Addreses the Watcher's Evolution and 'Epic' Season 2 Finale - CBR - Comic Book Resources - December 31st, 2023 [December 31st, 2023]
- Evolution of the Connected Autonomous Vehicle - Ward's Auto - December 31st, 2023 [December 31st, 2023]
- A project to capture the evolution of human culture. - Psychology Today - December 31st, 2023 [December 31st, 2023]
- The Evolution of a Digital Soul. Beyond Code: A Journey of Heart and | by Mark Randall Havens | Dec, 2023 - Medium - December 31st, 2023 [December 31st, 2023]
- 4 Clues That Reid Is Finally Returning In Criminal Minds: Evolution Season 2 - Screen Rant - December 31st, 2023 [December 31st, 2023]
- Evolution of Samoyed and Kitten's Friendship Delights Internet: 'Wholesome' - Newsweek - December 31st, 2023 [December 31st, 2023]
- Crypto Evolution: Pullix (PLX) vs OKB (OKB) & KuCoin (KCS) - Crypto Reporter - December 31st, 2023 [December 31st, 2023]
- Alfa Romeos mediocre F1 season heralded its era of evolution: Prime Tire - The Athletic - December 31st, 2023 [December 31st, 2023]
- Beyond The Uniform: 10 Years of Evolution in SYNC Performance's Custom Program - SkiRacing.com - December 31st, 2023 [December 31st, 2023]
- Why SZA's evolution into a popstar has earned her recognition as artist of the year - Salon - December 31st, 2023 [December 31st, 2023]
- AI in 2023 Rises, Falls and Evolution - Finance Magnates - December 31st, 2023 [December 31st, 2023]
- Indonesia's Indosat pursues evolution from telecom to tech company - Nikkei Asia - December 31st, 2023 [December 31st, 2023]
- EdTech Evolution: 3 Stocks Educating the Next Generation - InvestorPlace - December 31st, 2023 [December 31st, 2023]
- Informa Tech Interview with Huawei about voice evolution and innovations at 5G Core Summit 2023 - Informa Tech ... - Light Reading - December 31st, 2023 [December 31st, 2023]
- Looking ahead: What will the DeFi evolution look like in 2024? - Ledger Insights - Ledger Insights - December 31st, 2023 [December 31st, 2023]
- Why Cat Bohannon wrote 'Eve, How the Female Body Drove 200 Million Years of Human Evolution' | India News ... - IndiaTimes - December 31st, 2023 [December 31st, 2023]
- The smart-design evolution of the laboratory space - pharmaphorum - December 31st, 2023 [December 31st, 2023]
- The WILD Evolution of Teenage Mutant Ninja Turtles TMNT (VIDEO) - FandomWire - December 31st, 2023 [December 31st, 2023]
- The supernatural invades American museums via indigenous artifacts - Why Evolution Is True - December 31st, 2023 [December 31st, 2023]
- Baleen Whales First Evolved Large Body Size in Cold Southern Waters, New Fossil Shows - Sci.News - December 31st, 2023 [December 31st, 2023]
- The Evolution of Identity in Taiwan The Diplomat - The Diplomat - December 31st, 2023 [December 31st, 2023]
- From the Archive: The Evolution Of Hockey Pools - The Hockey News - December 31st, 2023 [December 31st, 2023]
- 'X-Men: Evolution' Is Better Than 'X-Men: The Animated Series' - Collider - December 31st, 2023 [December 31st, 2023]
- Unveiling the Silver Screen: The Evolution of Celebrity Nudity in Cinema - The Hype Magazine - December 31st, 2023 [December 31st, 2023]
- Are Humans Still Evolving? 'Maybe More Rapidly Than Ever,' Says Scientist - Newsweek - December 31st, 2023 [December 31st, 2023]
- The Intersection of Real Estate and Fintech: Evolution, Impact of Policies, and Global Dynamics - CXOToday.com - December 31st, 2023 [December 31st, 2023]
- Kyle Richards' Style Evolution: Her Best Looks - Us Weekly - December 31st, 2023 [December 31st, 2023]
- Criminal Minds: Evolution Season 2's "Deeper Secrets" Teased By Aisha Tyler - Screen Rant - December 31st, 2023 [December 31st, 2023]
- Saturday: Hili dialogue Why Evolution Is True - Why Evolution Is True - December 31st, 2023 [December 31st, 2023]
- NBA 2K24 MyTEAM New Year Resolution Adds 14 Evolution Cards - ClutchPoints - December 31st, 2023 [December 31st, 2023]
- dive into the history of NASA's logo evolution from the space ... - Designboom - November 8th, 2023 [November 8th, 2023]
- Resolving the puzzle of same-sex sexual interactions - Nature.com - November 8th, 2023 [November 8th, 2023]
- The History and Evolution of Black Friday And How It Got Its Name - Yahoo Life - November 8th, 2023 [November 8th, 2023]
- Evolution of Terran R, with Tim Ellis (Relativity Space) - Payload - November 8th, 2023 [November 8th, 2023]
- Brownell Raves About Breakout Junior's Evolution - The Clemson Insider - November 8th, 2023 [November 8th, 2023]