The Art of Manliness - The Strange Science of Sweat

00:00:00.000 start jogging around the block or simply sit outside on a hot summer day and you begin to

00:00:10.900 feel moisture develop all over your body maybe you drop a sweat roll down your face clothes

00:00:15.040 start to get sticky you start feeling in greater intensity a process that's actually going on all

00:00:19.560 the time sweating you may never thought too much about your sweat or perhaps been a little

00:00:23.540 embarrassed by it when your sweat becomes noticeable in a socially delicate situation

00:00:27.060 but my guest today says that human sweat is in fact incredibly fascinating and something you

00:00:31.040 should embrace with real appreciation and enthusiasm her name is sarah evarts and she's a science

00:00:34.960 journalist and the author of the joy of sweat strange science of perspiration sarah and i begin

00:00:39.320 our conversation with what sweat is the two kinds your body produces and how human sweating is unique

00:00:44.020 in what sarah calls our species superpower we then get into the surprising quickness with which the

00:00:48.560 things we drink start coming out of our pores why we sweat when we're anxious or nervous whether how

00:00:52.900 much you personally sweat comes down to genetics or environment and why the fitter you are the

00:00:56.980 more you sweat sarah impacts whether there are differences between how men and women sweat and

00:01:00.740 smell whether our dislike for body odor is innate or culturally conditioned why some people are

00:01:05.200 smellier than others and the role that smell and pheromones play an attraction sarah also explains 0.84

00:01:09.560 whether antiperspirants are bad for you and if you should switch to a natural deodorant and we

00:01:13.120 end our conversation with why it feels so good to make ourselves intentionally sweaty through things

00:01:17.060 like a sauna and whether hitting the sauna can detox your body after the show's over check out our

00:01:21.120 show notes at aom.is sweat all right sarah everts welcome to the show it's great to be here so you've

00:01:34.080 got a book called the joy of sweat the strange science of perspiration and this book had you traveling

00:01:39.300 around the world talking to scientists about sweat so how did that happen how did you end up traveling

00:01:46.820 the world you went to germany i think you went to different countries i think russia at one point

00:01:52.540 to research about sweat how'd that happen well you know i'm a science journalist and you know a long

00:01:59.280 time ago i was a chemist but i'm also a person who was like always slightly afraid that i might sweat a

00:02:05.940 little bit too much and you know at some point i kind of decided you know let's just uh like dig into the

00:02:13.540 research on sweat instead of like being anxious about it and so yeah i tracked down people who were

00:02:20.240 doing scientific analyses of sweat and then also people who are kind of playing around with cultural

00:02:25.380 taboos and yeah for example that's how i ended up in moscow at a sweat dating event and so something you

00:02:32.720 highlight in the book is that sweat is something we all do but sweat has pretty much gotten the short

00:02:37.660 shrift in scientific research what's going on there why is that yeah it's really interesting because

00:02:42.780 like if you just like look at the scientific literature you see that compared to say pee um

00:02:49.680 sweat has like an order of magnitude less articles about it and you know you wonder if if scientists

00:02:55.380 just wondered if it was just salt and water and actually sweat is so much more interesting than that

00:03:03.300 because it's sourced from the watery parts of blood pretty much anything that's circulating around in

00:03:10.640 your blood system kind of emerges out in sweat because your sweat glands you know once the big

00:03:16.820 things in in blood like red blood cells platelets immune cells are filtered out all that liquidy stuff

00:03:22.120 gets dispatched to your skin when you're too hot all right okay so that's interesting we'll talk more

00:03:26.860 about what makes up sweat but that's something i learned like what is sweat well it's salt and water

00:03:31.940 because we've all tasted our sweat probably but i didn't know it came i didn't know it came from your

00:03:35.940 blood like it's just basically your blood yeah it's it's the the liquidy parts so effectively

00:03:42.560 you have that's called blood plasma and you know when you cut open a body you know i don't mean that

00:03:48.800 in like a horrific way like our bodies are wet inside right there's there's moist liquid around all of

00:03:55.040 our organs that's called interstitial fluid and so interstitial fluid comes from blood plasma that

00:04:00.700 liquidy parts of blood and then when we overheat and our sweat glands get the like big directive to

00:04:08.200 open the floodgates well what do they do they go to that interstitial fluid and they dispatch it to

00:04:14.560 the surface because when you evaporate water this kind of consumes heat and so the sweat evaporation

00:04:22.940 effectively whisks heat away from your hot body and out into the atmosphere you also mentioned the book

00:04:29.720 okay sweat is primarily salt and water but there are two types of perspiration right you have two

00:04:34.360 types of sweat pores what are those two types of sweat pores and what's the difference between the

00:04:38.000 sweat that comes out of each one out of our sweat pores that cover our body we have about

00:04:44.760 two to five million i have three million sweat pores that is called eccrine sweat and that's that 0.55

00:04:51.060 liquidy part of the blood that's responsible for helping us cool off but there is another kind of

00:04:57.080 sweat gland and that's the one that appears in armpits at puberty it's called the apricline gland

00:05:03.240 and its sweat is actually not watery or salty at all it's very waxy it's actually pretty similar

00:05:09.940 to earwax and when that sweat starts coming out anywhere where hair grows at puberty bacteria living in

00:05:18.880 your armpits eat and it's their metabolites effectively bacteria poop that is that stinky smell that starts

00:05:27.000 wafting out of armpits from the teenage years onward we'll talk a little about bo here in a bit but

00:05:33.100 do we know why we have that special armpit gland like why do we sweat that what's the purpose of it 0.74

00:05:39.000 right that's stymied scientists for a long time but many think that it does have to do with what's

00:05:45.240 called chemical communication that or odorous communication that this is a way that we share information

00:05:52.600 about ourselves to other humans and it probably had more of a role earlier in our evolutionary history

00:05:59.220 but it's kind of like vestigial it's still there around and then of course some people speculate

00:06:04.700 that it's involved in you know sexual maturation that it's somehow involved in you know love or at

00:06:12.880 least romance because it appears at puberty right when everything else gets cracking for procreation 0.77

00:06:18.340 all right and that connects to the subject of pheromones and we're going to talk about that

00:06:21.960 here in a little bit but let's talk about the idea of sweating in the animal kingdom in general

00:06:26.460 so all animals have to keep themselves cool somehow because just living creates heat through metabolism

00:06:32.260 and if you don't cool yourself off you're going to die but the way humans cool off with sweat is

00:06:38.220 different from other animals how so right so sweating as much as it's kind of gross to a lot of people

00:06:44.460 it's actually our superpower in the animal kingdom it's one of the things that makes us unique along

00:06:51.160 with nakedness and the reason it's such a superpower is that it allows us to cool down while we're on the

00:07:00.120 move so if you can imagine in our history you know many of the prey that we needed to hunt sprints

00:07:07.200 faster than us but because we have this huge surface area for evaporating off water getting rid of

00:07:14.340 our body heat we can cool down while on the run and so our prey you know sprints away super fast

00:07:19.960 but then they have to stop and cool down because death by heat stroke a terrible way to die and you

00:07:26.820 know eventually we can catch up forcing them to sprint away and sprint away and sprint away until

00:07:30.920 they're so weakened by heat stroke that you know they're easy to to kill or to hunt and what's so

00:07:37.560 amazing about humans is our naked skin surface right so if you think about a dog panting we all know

00:07:45.380 that's how dogs cool down it is evaporating away water because that's the best way to cool your body

00:07:52.180 down but it's doing it off the only naked surface that it has its tongue right and instead humans have 0.99

00:07:59.360 our whole bodies to do that on and even chimpanzees are our closest evolutionary neighbor or relative

00:08:06.340 although they have sweat glands over their whole bodies many many primates do not all but some

00:08:11.700 they are cooling down by panting because you know our naked bodies have that surface area and you know

00:08:19.380 the modern incarnation of this is you know we can run marathons we're really good at you know not

00:08:25.500 dying of heat stroke while we're exercising heavily yeah we uh had daniel lieberman on the podcast and i

00:08:33.260 think you talked oh he's great yeah and he talked about there's they've done he's done a race with

00:08:37.680 horses like so it's like a long distance race where he raced a horse and in the beginning the horse was

00:08:42.720 beating him but eventually the humans all beat the horses because the humans can keep going because the

00:08:47.320 horse at the stop because they overheat and they have to cool down exactly and what's kind of also amazing

00:08:53.440 is that because this like evaporation of water is so important for staying cool animals dispatch other

00:09:02.940 bodily fluids whatever they have available to the surface of their their bodies to get rid of heat

00:09:08.640 and you know you know dogs use saliva but you know seals rely on urine honeybees vomit on themselves

00:09:16.580 all to get their bodies wet so that it can away heat and the thing about humans is a we've got

00:09:24.520 specialized glands just to do this number one and number two we do it so much more efficiently than 0.98

00:09:31.280 than all other animals and so yeah it really is our kind of amazing evolutionary superpower and if you

00:09:37.280 know what evolution could have bequeathed us like we could be cooling down from pee like would you know

00:09:44.300 that sweat is so much less gross right yeah i'm grateful i don't have to pee myself to cool myself

00:09:49.820 down so let's talk a little bit more about sweat so one of some of the research that's been going on

00:09:55.680 is trying to figure out how soon does the water we consume become sweat and i think that also we

00:10:03.400 need to ask too is like how often are we sweating are we sweating all the time or do we only sweat when

00:10:07.560 we get you know reached a certain temperature right we are sweating all the time if we weren't

00:10:13.220 we would be freaking miserable right our body's constantly making micro adjustments and most of

00:10:20.720 the time when we notice sweat it's because we've you know upped our activity and so our sweat glands are 0.60

00:10:26.780 like on hyperdrive and they're like crap we got to get going right but at any moment your body is

00:10:32.960 releasing a tiny amount of sweat to make micro adjustments to your internal temperature and so

00:10:39.120 you know as as a result we do need to drink water to stay hydrated and uh there's this awesome

00:10:45.980 scientist that you're kind of referring to this guy named michael zek who really likes going to the

00:10:50.900 sauna and uh one time he was like in the sauna getting philosophical with his buddy and they were like

00:10:57.580 hmm you know i wonder how quickly you know when you drink a glass of water how quickly does that water

00:11:05.020 you know get absorbed by your intestinal tract get you know put into your blood get dispatched to your

00:11:12.300 you know internal organs percolate to your skin and then emerge out in sweat and you know when most of us

00:11:18.660 get philosophical in the sauna you know that's the end of that but because he's a scientist he could do the

00:11:24.380 experiment and so he spiked his favorite rehydration drink which in germany for him is this weird

00:11:32.820 combination 50 50 cola 50 50 wheat beer it's kind of like a brown shandy and uh so he spiked it with

00:11:42.040 this chemical that he could measure and that's not normally found in our bodies or in our sweat

00:11:48.380 so he drinks his cola weizen it's what it's called and then quickly undresses gets into the sauna and starts

00:11:56.140 measuring and capturing the sweat coming out of his skin at timed intervals and he found that

00:12:02.260 it took 15 minutes for that chemical tracer that he had put in his drink to come out of his sweat

00:12:08.860 pores which is pretty fast right that is really fast i didn't think it would be that fast

00:12:13.280 no neither did i he he made me guess um and i i guess closer to an hour but uh yeah nope it's really

00:12:20.460 fast so sweats primarily to regulate our body temperature but we also sweat when we're anxious

00:12:26.840 nervous why do we do that that's super interesting to me so there's like a lot of speculation about

00:12:34.980 this one idea that uh researchers have is that it's kind of anticipatory right when we're anxious

00:12:42.900 for most of human history we've had to like run really fast away from the thing that we're scared of

00:12:48.700 and so it might be our body effectively predicting from anxiety that we're going to be running and thus

00:12:55.940 turning up the heat and that it would be wise to perhaps start the cool down strategy pronto but

00:13:03.500 it's also this really interesting kind of vestigial aspect of evolution so remember how i said humans

00:13:10.460 have these salty sweat glands over our whole body we've got millions of them and what's really

00:13:16.820 interesting is that all mammals have those salty sweat glands but they're only located for most mammals

00:13:24.160 in their paws and that was because initially this eccrine sweat this kind of salty you know watery

00:13:31.580 parts of blood was used for grip for climbing and effectively when an animal got scared and had to like

00:13:38.060 run away possibly up a tree that's a little bit of that sweat would come out to help them with grip

00:13:43.560 and so you know when you're stressed out and notice that your hands are getting sweaty it's a vestigial

00:13:50.660 response um from you know your your mammalian predecessors that had to climb a tree in their anxious moments

00:13:59.040 interesting so another thing you highlight too is sweat works better in certain climates than others and

00:14:05.300 keeping it cool so the whole cooling mechanism is evaporation how does climate affect how effective

00:14:12.660 that evaporation cooling is yeah so you know in a hot climate you can imagine the sweat is evaporated

00:14:23.140 much more quickly away and that's due to some chemistry that you may have learned in high school

00:14:28.880 like in a very humid place there's already a lot of evaporated water in the atmosphere and it's kind of

00:14:38.520 giving a pushback to the water on your skin that's trying to evaporate to whisk away heat and so in a

00:14:45.920 desert the water that you emit with sweat really evaporates quickly and so that's really good for

00:14:53.480 cooling it's not good for for hydration that's why in many very dry climates you're advised to wear

00:15:00.700 cool loose clothing so that you kind of keep a little bit of humidity at your skin surface right

00:15:06.760 but in really super sweaty climates or humid climates sorry you want to take off as much clothing as

00:15:13.760 possible to effectively give all those water molecules on your your skin a chance to to get

00:15:20.120 out and away even when there's already a lot of water molecules around in the atmosphere kind of taking

00:15:26.500 up space all right that's a good practical takeaway there keep me cool i live in oklahoma it's really

00:15:31.020 humid here so wearing lots of loose clothing during the summer not probably a good idea

00:15:36.560 but if i were in arizona yes yeah exactly and if you think about what a dog does while they're

00:15:44.260 panting the whole reason that they're heaving in and out like the panting part right is they are

00:15:50.300 trying to push all that water that is just evaporated up off their tongue and is making the surface just

00:15:58.280 above their tongue dense with water molecules they're heaving all that wet air away and allowing

00:16:05.300 drier air to come on top of their tongue to make more room for more water molecules so that's the

00:16:11.380 whole point of panting is to kind of move that wet air away as fast as possible especially since

00:16:17.040 they don't have a lot of surface area for this cooling strategy well let's talk about how sweating

00:16:22.060 differs across populations so you you started this book because you thought well i'd probably sweat more

00:16:26.680 than most people and you just told me you have three million sweat pores how what influences how much

00:16:31.800 we sweat is it primarily genetics or can our environment also play a role yeah it's a bit of

00:16:38.400 nature and nurture situation so certainly um some families are sweatier than others and that could be

00:16:46.140 due to you know just the number of sweat pores that you have on your body there's quite a range also

00:16:51.740 like the flux out of your sweat glands so how quickly the sweat is coming out that's a big range and

00:16:59.400 your genetics might mean that you have a bigger flow than i do or i probably have a bigger flow than

00:17:05.980 you and then there's also you know how quickly how responsive your body is to temperature changes

00:17:12.160 but what's really interesting is this nurture side and evolutionary biologists are are really digging

00:17:19.060 into this right now because when you're born you're born with all the sweat glands that you're

00:17:25.020 gonna have like sweat glands are developed in utero but they don't all become active at birth it's only

00:17:33.100 in your toddler years that like they come you know to become fully operational so to speak and so in

00:17:39.540 those first early years of your life your body is cluing into the environment in which you live and

00:17:45.340 and learning whether you know you're in a super hot place and so you have to maybe be a bit more

00:17:51.480 active or more efficient or whether you're in a cool place and so yeah there's this mix of both you

00:17:57.260 know what you have genetically and you know where you spent your early years i mean the take-home message

00:18:03.380 though is that you can blame your parents for both because uh they're responsible for your genetics and

00:18:09.060 you know also presumably where you spent your toddler years well let's say someone is born in a

00:18:14.680 cool cold dry area and then they move to florida for example will their body adapt and sweat more or less

00:18:24.540 based on that that move right so there your body's uh acclimatized right so you know but they do it a 0.75

00:18:33.700 little bit slowly and then you have this like baseline which you start with so you know for example

00:18:39.740 right now athletes are prepping for tokyo where it's super humid and super hot some say it might

00:18:45.880 be the hottest olympics ever and so they are all training in extremely hot weather so that their

00:18:52.800 bodies can figure out how to be efficient at cooling in extremely humid hot weather so you do there is this

00:19:00.560 process where your body does learn to adapt but at some point we all have a baseline and that baseline is set

00:19:08.240 in your your toddler years and so yeah you know there are some micro adjustments but um at some

00:19:14.360 point you're stuck with what you have we're gonna take a quick break for your words from our sponsors

00:19:18.540 and now back to the show something i've read i don't know where i read it maybe on the interwebs or

00:19:27.000 on like in a men's health magazine from 1992 or something uh is that the fitter you are the more

00:19:32.540 you sweat is there anything to that well yeah because if you are super fit right your body has

00:19:40.140 learned that when you start exercising when you start dialing up the temperature you are not going

00:19:45.760 to be doing this for you know 30 seconds or even you know 15 minutes you're probably going to be doing

00:19:51.440 this for like over an hour and so athletes actually have a tendency to sweat more the more that they train

00:19:59.840 and the and the fitter that they are and this is also true for people who kind of have sauna going

00:20:05.280 as as a hobby so for example i noticed that when i moved to germany and you know wanted to you know

00:20:12.660 integrate with the locals who are all obsessed with going to to the sauna that my sweating rates got

00:20:18.860 faster and more voluminous because i was suddenly going to the sauna not just for you know a one-time deal

00:20:26.240 but like going regularly and spending a heck of a lot of time in a really hot space so ultimately

00:20:31.500 it's all part of this like acclimatization process where your body is like learning about your behavior

00:20:37.760 and figures out that oh geez when the temperature rises she's going to be in there or he's going to 0.98

00:20:44.960 be in there for a heck of a long time let's get cracking on the cool down directive are there

00:20:50.140 differences between men and women and how they sweat not really so generally uh any differences

00:20:57.140 that you see are most likely just due to volume to surface area issues there's not anything really

00:21:05.300 biologically different in how sweat glands work or or how many there are but because you know men are 0.94

00:21:11.980 on average larger than women they've got slightly more sweaty activity because they've got that much more 1.00

00:21:19.580 body to keep cool well let's get to the fun stuff here which is like why sweat smells and like the social

00:21:27.200 aspect of being smelly humans so you mentioned earlier that one type of sweat forgot the name of the gland

00:21:33.600 the sweat pore that produces starts with an a right oh apocrine yeah the apocrine sweat that's the stuff

00:21:40.440 so the bacteria on our skin and our armpits starts eating that stuff and the bacteria fart and that's

00:21:47.360 basically our bo why do i guess i would say i think americans or westerners in general like why do we

00:21:54.700 find bo so off-putting like why don't we like it well so i would say two things i think that americans

00:22:02.040 take it to a whole nother level of of insecurity but i would say that for much of human history people

00:22:09.420 have been kind of worried about the odor of themselves so one of my favorite quotes which is on my wall right

00:22:17.100 now it's advice from the roman poet catullus so literally like two thousand years ago um to his

00:22:22.980 friend and then his nemesis this guy named rufus he says um wonder not rufus why none of the opposite

00:22:29.700 sex wishes to place her dainty thighs beneath you not even if you undermine her virtue with gifts of 0.99

00:22:36.120 choice silk or the enticement of a pellucid gem you're being hurt by an ugly rumor which asserts that 0.97

00:22:42.520 beneath your armpits dwells a ferocious goat this they fear and no wonder for it's a right-ranked

00:22:48.360 beast that no pretty girl will go to bed with so either get rid of this painful affront to the 1.00

00:22:53.020 nostrils or cease to wonder why the ladies flee so i love that because you know it speaks to the fact

00:22:59.600 that you know for at least two thousand years we've been a bit worried about our body odor but most of

00:23:06.940 that time the way that we've dealt with it is to wash with water possibly soap and or apply a huge

00:23:14.740 amount of perfume to kind of overwhelm our bo and it wasn't really until the turn of the 20th century

00:23:22.300 when what we you know use now deodorant and antiperspirants get invented and so up until this

00:23:28.840 point people have a background body odor of of each other they know each other's body odor really

00:23:35.400 really well and you know it kind of reminds me of the difference between smoking laws right back in

00:23:42.460 the day you know you'd go to a bar and there would be tons of smoke and you'd go home and you wouldn't

00:23:47.900 notice it and now because we have made this very you know smoke-free environment when you do go to a

00:23:54.460 very smoky place it's all the more like you notice it so much more it feels so much more intense so over

00:24:02.520 the 20th century we dialed down you know our body odor uh to the those around us a lot more because

00:24:10.620 of these products but you know simultaneously those that marketed these products used this thing

00:24:17.260 invented this thing called whisper copy which puts the fear of stink in humans and you know in the

00:24:23.900 1919s they started their advertising strategies towards women and then they started trying to convince

00:24:30.020 women to buy deodorants and antiperspirants by saying listen you know if if you sweat you stink 1.00

00:24:36.520 and people are talking about you behind your back and not only is this gossip hurting your reputation

00:24:43.000 but it's going to completely negate your ability to find a man right it's the 19 you're going to be an

00:24:47.700 old maid and you know eventually you're going to be an old maid right and you know eventually by by the

00:24:53.540 1930s when they've you know got the fear of stinking so many women that they've maxed out the the market 1.00

00:24:59.920 chair and they're like oh now we we still want to make more money they're like hmm what what should

00:25:04.940 we do oh dudes smell too but you know by this time they've spent a couple of decades uh presenting

00:25:11.580 this presenting deodorants and antiperspirants as a feminine product and so they have to like 1.00

00:25:16.360 dial up the the masculinity in their advertising strategies and so they put deodorants and antiperspirants

00:25:23.200 into like the manliest things they can imagine which in that case at that time was like a whiskey

00:25:28.000 jar so they're like selling deodorants out of whiskey jugs but also their their tactics still

00:25:35.060 rely on this thing called whisper copy right putting social fears of exclusion in men but instead of

00:25:41.980 focusing on on romantic exclusion they initially tell men because it's the 30s you know the depression

00:25:47.380 that they're going to lose their job or they're not going to get a promotion that effectively uh stinking

00:25:53.440 in the boardroom is going to hurt your career and nowadays you see you know both of these strategies

00:26:00.600 you know fear of social exclusion at work or or you know in love being applied to to everybody equally

00:26:06.700 but yeah it's that whisper copy this this fear and and you see this a lot in north america

00:26:12.880 let's talk about the smell of bo so the the quote you listed the guy described it as smell like a goat

00:26:19.280 how do scientists i mean you just there's people who they smell armpits for a living to try to figure

00:26:24.760 out what is yes how do they describe the smell of bo so i've always think it's like it smells like a

00:26:30.820 like a onion whopper burger what's the scientific description of it i have not heard that and i love

00:26:39.040 it but yes uh so when scientists uh sniff armpits they actually chemists actually measure the molecules 0.56

00:26:47.740 coming off of an armpit and they have actually found what's known as two top notes um and one

00:26:55.880 smells kind of goatee kind of like feedy goatee smell and the other one smells like overwrite

00:27:03.220 kind of like tropical fruit with a touch of onion so your onion whopper burger is not like totally off

00:27:10.740 and so these two top notes are you know the reason that when you go into an elevator and you're like

00:27:18.760 whoa there was a really stinky person here before me you know that it was a human instead of say you 0.73

00:27:24.740 know a stinky dog or or a stinky horse and those those two top notes are the things that dominate our

00:27:31.020 body odor even though there are actually hundreds of other odorous molecules that kind of like add to

00:27:37.420 our symphony of smell um and you know it's the kind of relative proportions that give you your

00:27:44.300 own odor print that is distinguishable from my odor print at least to a dog who's say tracking you versus

00:27:51.080 tracking me are some people smellier than others yeah yeah is that just genetics you know you know

00:27:59.860 it's due to you know the bacteria that you produce or not produce but that you recruit into your

00:28:06.680 armpits right so you know we know about our human microbiome you know we've got trillions of

00:28:11.300 bacteria in our inside our digestive tract but also all over our skin and you know for the most part

00:28:17.580 this this bacteria is acting as a really helpful defense against pathogens but also in our armpits

00:28:26.400 that particular ecosystem attracts what's known as a corinobacteria as well as you know staphylococcus and

00:28:33.360 a whole bunch of others but people who have a higher proportion of corinobacteria in their armpits

00:28:39.100 often have a more potent pong and the crazy thing is the craziest story i read in the book that really

00:28:45.820 stuck to me was the guy who wasn't really smelly but then he was amorous with a woman and then after

00:28:53.980 that he just smelled he had a bo problem and he kind of did he did some like amateur scientific stuff

00:29:00.060 and figured out i think i got some of her bacteria on me now i'm now i'm a smelly guy yeah well he

00:29:05.000 turned it into a phd project and effectively was super interested this was like in the early days of

00:29:12.740 microbiome research and you know although we've known for a long time that the actual source of

00:29:19.160 our odor is you know the byproducts from these microbes he thought okay well you know there's this

00:29:26.640 idea of probiotics right like can you introduce good bacteria and could i possibly reintroduce my

00:29:34.400 good bacteria because yeah he had this experience where after an amorous trist his whole body odor 1.00

00:29:41.180 changed dramatically and it was you know quite alarming for him and ultimately he managed to

00:29:46.980 repopulate his own body with his own bacteria because he's now in the process of his phd like analyzing

00:29:54.600 exactly the like microbial membership of his armpit right he has those skills and he ended up having

00:30:02.280 this t-shirt that he had used for years to paint you know when he had to like paint a room in a house

00:30:08.040 and it had i guess the you know bacterial populations of his pre-amorous trist self and so when he he put it

00:30:18.340 on to paint the house he noticed after that that he he had managed to turn his body odor back to you 0.66

00:30:24.980 know back to normal uh for him oh so this guy not as stinky the lady that he slept with stinky but 0.98

00:30:33.320 generally are there differences between the smell the bo smell of men and women so not a heck of a lot

00:30:40.140 but you know there are some studies that have shown that you know of these two top notes that i was

00:30:44.900 talking about that men have a higher proportion of the like stinky goatee odor i mean that women have 0.98

00:30:52.560 a higher proportion of the tropical fruit overripe oniony odor but quite honestly you know everybody

00:31:01.180 produces both of these things in their armpits but yeah it's it's you know slightly proportionally

00:31:06.700 higher for women to produce the oniony odor and men the goatee one well let's get to why you went to 0.92

00:31:13.880 moscow you went to a basically it was like a smelling dating thing basically people were getting

00:31:20.820 sweat and you were getting matched with another person based on your sweat and i think people

00:31:26.340 have heard this idea of pheromones right like you can buy cologne with pheromones and it'll 0.94

00:31:30.520 some sort of like love potion and people will be attracted to you oh my god we have to talk about

00:31:34.280 that after right well is there anything to this idea that there are pheromones in our sweat and

00:31:40.360 being exuded by our body odor that makes us attractive to other people well because a good

00:31:45.660 chunk of our body odor appears in the sweat glands that produce sweat that you know show up at puberty

00:31:51.900 and you know puberty is when we become sexually mature you know people think or people suspect that

00:31:58.740 there's got to be some sort of role that our body odor plays in you know mating and so people have

00:32:07.120 spent you know decades trying to track down a human pheromone out of our armpits and you know they've

00:32:15.700 gotten a lot of really tantalizing clues like i think a lot of people have heard of this one experiment

00:32:22.040 where women were given t-shirt samples worn by men and the women found the men to be most attractive

00:32:31.420 when their immune systems were different enough that should they procreate their progeny would have

00:32:40.000 a super strong immune system and if you you think about that it makes evolutionary sense because

00:32:44.520 you know for a lot of human history our major foe has been microbial right plagues infections things

00:32:52.160 like that and so it behooves us if you're gonna mate to mate with somebody who's gonna give your

00:32:58.400 your progeny a chance at survival by having a great immune system but even though you can do

00:33:04.800 these experiments by like you know asking women to pick you know the odor that they like and and you

00:33:09.720 know analyzing the blood of everybody and being like yes this would be a good immune match in terms

00:33:15.060 of like plucking out of our body odor a molecule that is you know known as a human pheromone that's

00:33:22.440 eluded chemists and actually when you know about what a sex pheromone in the animal kingdom does it

00:33:30.460 kind of is probably a good thing so for example a bombacall is this pheromone that moths make and when

00:33:38.560 a female releases bombacall literally every male in the vicinity makes a beeline towards her it is like

00:33:45.420 the scientific definition of a booty call or wild pigs so when male wild pig breathes heavily on a

00:33:54.800 female in heat a set of pheromones called androsanol and androsanone that is like in his saliva and kind

00:34:02.960 of like percolates up in his heavy breathing when she sniffs that she immediately turns around and lifts 0.99

00:34:09.800 her rump in the like universal sign that you know it's time to start a family so that kind of like 0.99

00:34:17.640 instant you know reaction is you know a little bit alarming if you think about you know the human world

00:34:27.040 like it's just as well we haven't actually isolated a human sex pheromone because yeah that could be a

00:34:34.680 little dire and that hasn't stopped online entrepreneurs from selling kind of pseudoscience

00:34:41.160 potions that they call human pheromone colognes that like sound scientific and typically include

00:34:47.140 androsanol and androsanone so these are those wild pig pheromones and they are found in the armpits of

00:34:53.680 humans right but both men and women produce them equally so it can't be a pheromone right it can't be 0.99

00:34:59.260 a message from one you know for example biological sex to another but you know if you wear one of

00:35:05.560 those pheromone colognes you just might attract a female but it's going to be a female wild pig rather 1.00

00:35:11.860 than a female human and you know no judgment if that's your goal but yeah it's probably not what

00:35:18.240 most of the people buying those things want but in terms of like romance you know this kind of notion

00:35:25.020 of a human pheromone people say oh yeah you know i fell in love with him or her because of you know

00:35:31.100 the way that they smelt right about their unique odor print as opposed to what we know from the strict

00:35:38.620 definition of a sex pheromone which would work equally on literally every member of the human

00:35:44.080 species right it's not it's anonymous it's not unique it's not the thing that made you fall for

00:35:51.100 you know whoever you fell for as your one and only but so okay so basically there's the scientists

00:35:56.940 there's something going on because you know people can detect differences and i think was another study

00:36:01.240 too like men find the smell of women ovulating more attractive than women who aren't wasn't there a 1.00

00:36:09.480 study like that with t-shirts yeah so lap dancers yeah lap dancers got more tips they suspect there's some

00:36:15.720 kind of odor going so like scientists there's something going on but they just don't know what

00:36:19.440 basically is what what's going on yeah that is pretty much basically what is going on and there

00:36:25.300 are so many molecules percolating out of armpits that yeah it's it's been a long hard road and many

00:36:32.820 researchers have like really tried to to pluck out something that's like giving us a strict cue that

00:36:40.360 like i want to mate with you and that so far has you know been unsuccessful well another thing that

00:36:47.360 can get transmitted via our body odor is fear have we figured out yes have you figured out what fear

00:36:53.480 smells like so that's a super interesting area of research so it kind of stems from the fact that

00:36:59.740 a lot of law enforcement folks say that when a person comes in for questioning for interrogation

00:37:07.020 that they come in smelling like themselves but after interrogation after all those tough questions have

00:37:13.000 been asked everybody leaves smelling the same of this like strong potent anxiety odor and when

00:37:20.280 researchers have you know tried to follow up on that anecdote again they found really interesting

00:37:25.680 evidence that this is true so they they gave people tight white t-shirts to wear and put them in front

00:37:32.600 of a television and had them watch kind of a nature documentary and then had them watch a really scary

00:37:39.280 movie so that they produced you know just their normal pong and then like super stressed out scared

00:37:45.900 body odor and when they presented those t-shirts to a panel of sniffers the sniffers could distinguish

00:37:53.360 you know from perfect strangers who was stressed out and who was just stinky right like who who was

00:37:59.580 actually fearful and who was just smelling and you know the the folks that with probably the most interest

00:38:06.400 in this is the military because you can imagine if you have a bunch of soldiers in a tank and one

00:38:12.260 starts getting really scared that this odor is going to be detected by others and you know it might

00:38:18.460 spread fear when all of these soldiers really need to you know stay focused and and hopefully a little

00:38:24.600 bit unafraid and so the military is interested in plucking out this anxiety odor molecule so that they can

00:38:31.260 effectively capture it like you would capture like a poison gas and you know there's other kind of

00:38:36.280 more dystopian applications that you can imagine you know if you figured out what that odor is the

00:38:42.380 one that is like this the smell of fear you could use it you know on crowds to do crowd control so

00:38:50.400 again chemists have been trying for a long time to pluck out that molecule they haven't so far been

00:38:55.880 successful but they are quite close well let's talk about deodorant and a person's a big circle back to

00:39:02.580 that so it became a thing in america the turn of the 20th century they're using the whisper copy saying

00:39:07.460 you'll be an old maid or a bum if you don't use deodorant but there's a difference between deodorant

00:39:13.620 and antiperspirants what is the difference and let's talk about antiperspirants you've been hearing

00:39:18.120 a lot about that uh that antiperspirants are bad for you and should use a natural deodorant

00:39:22.680 what does the research say about that sure so the main difference between deodorants and antiperspirants

00:39:28.940 is how they work to thwart sweat so deodorants have antiseptics in them and so effectively what

00:39:37.080 happens is you put on deodorant and you kill all the bacteria in your armpit including the ones that

00:39:43.120 cause odor right whereas antiperspirants plug your sweat pores in your armpit which include both like

00:39:51.060 the apocrine the ones making that waxy sweat that like bacteria like to eat and also just you know

00:39:57.400 the wet stuff that comes out when you're you're exercising and so antiperspirants work by literally

00:40:03.280 cutting off the food supply to the hungry bacteria and in doing so prevent odor from being formed and

00:40:11.540 that's why antiperspirants though also help you avoid wet patches whereas deodorants are just dealing

00:40:18.820 with odor and the way that antiperspirants plug pores and have always plugged pores like literally the

00:40:26.300 very first antiperspirant products relied on aluminum salts so it used to be aluminum chloride now it's a

00:40:34.680 more complicated aluminum salt but you know there's a lot of people who have fears about putting on a

00:40:41.320 product that's got aluminum in it in part because you know aluminum in in high amounts is a neurotoxin

00:40:48.140 that being said you know in terms of our earth we have you know evolved on a planet where aluminum is

00:40:56.720 one of the highest percentage metals in the mantle and a lot of the food for example that we eat like

00:41:03.520 sesame seeds even potatoes have high amounts of aluminum in them and so our body has evolved ways

00:41:12.100 to rid itself of of aluminum and that's usually through the kidney which filters out nasty stuff

00:41:19.080 not just aluminum from our blood and you know dispatches it out in pee and so because of this

00:41:26.700 like concerns about aluminum being a neurotoxin it is a neurotoxin there's been worries that you know

00:41:34.420 if you put on deodorants that you're going to up your body burden so much that it will give you

00:41:41.360 you know neurological problems or alzheimer's and you know all the research has been done on this for

00:41:48.280 decades and shows that there's really not a strong correlation at all between wearing antiperspirants

00:41:55.480 and alzheimer's it's not something to fear yet it kind of keeps coming back and actually the european

00:42:02.540 commission has a scientific committee that looks at consumer products and they recently revisited the

00:42:09.420 issue and forced the cosmetic care industry to to do some pretty sophisticated experiments to see

00:42:16.060 whether putting on antiperspirant effectively gets aluminum into your bodies at a level that is

00:42:24.260 dangerous and and they found that there was no cause for concern and you know those studies were

00:42:30.000 were published in 2020 so you know yeah aluminum is not great to ingest but we are getting it in our

00:42:38.220 bodies from eating and you know from all sorts of other things like lipstick and other things have

00:42:43.820 have aluminum in it but yeah it's probably by wearing antiperspirant every day it's probably not

00:42:50.140 you know pushing that aluminum body burden to to the point of of concern that being said i you know i

00:42:56.960 mix and match so you know when i have to you know for example stand up in front of a whole bunch of

00:43:02.340 people and i don't want to have sweaty patches because i'm like you know nervous i'll sometimes

00:43:07.760 wear antiperspirant and you know if it's a day where you know i don't have to do anything particularly

00:43:13.440 huge but i don't feel like smelling my own bo i'll you know put on deodorant so you know i i don't

00:43:19.460 think it's a huge cause for concern but yeah it has been one for for many years so we we sweat to keep

00:43:26.440 cool and it's an automatic process you have no control whether you sweat or not but cultures

00:43:32.320 around the world and across time they've come up with the practices where they can basically create

00:43:38.300 an environment where they purposely sweat so i'm talking saunas sweat lodges you know asian cultures 0.99

00:43:43.800 have similar like hot being really hot why do you think this is a universal across humanity where we

00:43:49.620 just want to sweat i mean what is it about getting really hot and sweaty that feels good

00:43:53.580 yeah we crave that catharsis and i think part of it is that you know when you work up a sweat

00:44:01.620 you effectively even say you go into a sauna or a jimjilbang in korea or a hamam in in the middle

00:44:08.580 east um you are effectively forcing your heart into a little tiny workout right because you go into this

00:44:17.220 really hot room and in order to cool down your heart starts beating fast to move the hot blood

00:44:25.260 in your interior out to the surface of your skin so that it can be cooled down by sweat evaporation

00:44:30.800 right so you you effectively get your heart pumping and that has knockdown effects where you know you

00:44:37.920 produce those same happy hormones that you get when you exercise profusely or go for a run the runner's

00:44:44.220 high the endorphins you also have like epinephrine that's that's being produced and so you do actually

00:44:50.100 get a biochemical high when you sweat profusely in a sauna so i think that there is this you know

00:44:56.880 feelings of joy and catharsis um that you get when you sweat in a sauna and also that you get if you

00:45:03.520 like really work out hard and have that you know euphoria that post-workout euphoria something you

00:45:10.120 didn't mention it doesn't detox oh yes that is the biggest myth this yeah if you ask me like what

00:45:16.320 is my you know my biggest sweat pet peeve it's this notion that sweating is a way to detox and that's

00:45:25.600 so totally wrong and it like reveals a fundamental misunderstanding of how our bodies work so remember

00:45:32.320 how i said that sweat is sourced from the watery parts of blood yes so if you were to detox by

00:45:40.960 sweating right where a detox the idea of a detox is like you get all the crap that's circulating around

00:45:46.700 your body out of your body right so if you were to detox by sweating you would literally have to

00:45:52.900 get rid of all the liquidy parts of your blood you would have to sweat out all your wet parts of blood 0.99

00:46:00.680 you would have to effectively dehydrate yourself at which point you would dry up and die that just

00:46:05.860 doesn't make sense instead our bodies detox using the kidney right so our kidney filters out all the 0.62

00:46:13.620 gunk in our blood right and dispatches out all the bad stuff in pee and anything that's coming out in

00:46:20.720 sweat is just incidental so yes certainly you can sweat out some some nasty things that are circulating

00:46:26.800 in your blood if they happen to be there but also you're sweating out you know glucose which your

00:46:32.020 body uses as energy and hormones anything that's in that liquidy part of blood and so this notion that

00:46:38.300 sweat is a detox strategy super super wrong and it's really good that we don't detox by sweating

00:46:44.320 because yeah you don't really want to dehydrate and die okay so yes sweating does remove stuff from

00:46:51.140 your body but that's just incidental you're not going to be able to purify yourself with just sweating

00:46:55.660 so when you go to the sauna just enjoy the sauna simply because it feels really good to get hot and

00:47:01.180 sweaty enjoy that little workout you get in there the endorphins just do it for this joy of sweat itself

00:47:06.980 exactly yeah well sarah this has been a great conversation where can people go to learn more

00:47:11.320 about the book in your work they can go to my publisher's website norton or my own website saraheverts.com

00:47:19.500 or they can you know grab the book off a shelf and and read it well saraheverts thanks for time

00:47:25.100 it's been a pleasure thank you so much my guest today was saraheverts she's the author of the

00:47:29.820 book the joy of sweat it's available on amazon.com and bookstores everywhere check out our show notes

00:47:33.820 at aom.is sweat where you can find links to resources where you delve deeper into this topic

00:47:38.180 well that wraps up another edition of the aom podcast check out our website at artofmanliness.com

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00:48:25.400 you

The Art of Manliness - July 19, 2021

The Strange Science of Sweat

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