The Strange Science of Sweat
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173.25378
Summary
In this episode, I speak with science journalist and author Sarah Evarts about the surprising quickness with which the things we drink start coming out of our pores, why we sweat when we're anxious or nervous, and why it feels so good to make ourselves intentionally sweaty through things like a sauna.
Transcript
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start jogging around the block or simply sit outside on a hot summer day and you begin to
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feel moisture develop all over your body maybe you drop a sweat roll down your face clothes
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start to get sticky you start feeling in greater intensity a process that's actually going on all
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the time sweating you may never thought too much about your sweat or perhaps been a little
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embarrassed by it when your sweat becomes noticeable in a socially delicate situation
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but my guest today says that human sweat is in fact incredibly fascinating and something you
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should embrace with real appreciation and enthusiasm her name is sarah evarts and she's a science
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journalist and the author of the joy of sweat strange science of perspiration sarah and i begin
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our conversation with what sweat is the two kinds your body produces and how human sweating is unique
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in what sarah calls our species superpower we then get into the surprising quickness with which the
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things we drink start coming out of our pores why we sweat when we're anxious or nervous whether how
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much you personally sweat comes down to genetics or environment and why the fitter you are the
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more you sweat sarah impacts whether there are differences between how men and women sweat and
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smell whether our dislike for body odor is innate or culturally conditioned why some people are
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smellier than others and the role that smell and pheromones play an attraction sarah also explains
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whether antiperspirants are bad for you and if you should switch to a natural deodorant and we
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end our conversation with why it feels so good to make ourselves intentionally sweaty through things
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like a sauna and whether hitting the sauna can detox your body after the show's over check out our
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show notes at aom.is sweat all right sarah everts welcome to the show it's great to be here so you've
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got a book called the joy of sweat the strange science of perspiration and this book had you traveling
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around the world talking to scientists about sweat so how did that happen how did you end up traveling
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the world you went to germany i think you went to different countries i think russia at one point
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to research about sweat how'd that happen well you know i'm a science journalist and you know a long
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time ago i was a chemist but i'm also a person who was like always slightly afraid that i might sweat a
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little bit too much and you know at some point i kind of decided you know let's just uh like dig into the
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research on sweat instead of like being anxious about it and so yeah i tracked down people who were
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doing scientific analyses of sweat and then also people who are kind of playing around with cultural
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taboos and yeah for example that's how i ended up in moscow at a sweat dating event and so something you
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highlight in the book is that sweat is something we all do but sweat has pretty much gotten the short
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shrift in scientific research what's going on there why is that yeah it's really interesting because
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like if you just like look at the scientific literature you see that compared to say pee um
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sweat has like an order of magnitude less articles about it and you know you wonder if if scientists
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just wondered if it was just salt and water and actually sweat is so much more interesting than that
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because it's sourced from the watery parts of blood pretty much anything that's circulating around in
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your blood system kind of emerges out in sweat because your sweat glands you know once the big
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things in in blood like red blood cells platelets immune cells are filtered out all that liquidy stuff
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gets dispatched to your skin when you're too hot all right okay so that's interesting we'll talk more
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about what makes up sweat but that's something i learned like what is sweat well it's salt and water
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because we've all tasted our sweat probably but i didn't know it came i didn't know it came from your
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blood like it's just basically your blood yeah it's it's the the liquidy parts so effectively
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you have that's called blood plasma and you know when you cut open a body you know i don't mean that
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in like a horrific way like our bodies are wet inside right there's there's moist liquid around all of
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our organs that's called interstitial fluid and so interstitial fluid comes from blood plasma that
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liquidy parts of blood and then when we overheat and our sweat glands get the like big directive to
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open the floodgates well what do they do they go to that interstitial fluid and they dispatch it to
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the surface because when you evaporate water this kind of consumes heat and so the sweat evaporation
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effectively whisks heat away from your hot body and out into the atmosphere you also mentioned the book
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okay sweat is primarily salt and water but there are two types of perspiration right you have two
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types of sweat pores what are those two types of sweat pores and what's the difference between the
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sweat that comes out of each one out of our sweat pores that cover our body we have about
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two to five million i have three million sweat pores that is called eccrine sweat and that's that
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liquidy part of the blood that's responsible for helping us cool off but there is another kind of
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sweat gland and that's the one that appears in armpits at puberty it's called the apricline gland
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and its sweat is actually not watery or salty at all it's very waxy it's actually pretty similar
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to earwax and when that sweat starts coming out anywhere where hair grows at puberty bacteria living in
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your armpits eat and it's their metabolites effectively bacteria poop that is that stinky smell that starts
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wafting out of armpits from the teenage years onward we'll talk a little about bo here in a bit but
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do we know why we have that special armpit gland like why do we sweat that what's the purpose of it
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right that's stymied scientists for a long time but many think that it does have to do with what's
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called chemical communication that or odorous communication that this is a way that we share information
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about ourselves to other humans and it probably had more of a role earlier in our evolutionary history
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but it's kind of like vestigial it's still there around and then of course some people speculate
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that it's involved in you know sexual maturation that it's somehow involved in you know love or at
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least romance because it appears at puberty right when everything else gets cracking for procreation
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all right and that connects to the subject of pheromones and we're going to talk about that
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here in a little bit but let's talk about the idea of sweating in the animal kingdom in general
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so all animals have to keep themselves cool somehow because just living creates heat through metabolism
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and if you don't cool yourself off you're going to die but the way humans cool off with sweat is
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different from other animals how so right so sweating as much as it's kind of gross to a lot of people
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it's actually our superpower in the animal kingdom it's one of the things that makes us unique along
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with nakedness and the reason it's such a superpower is that it allows us to cool down while we're on the
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move so if you can imagine in our history you know many of the prey that we needed to hunt sprints
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faster than us but because we have this huge surface area for evaporating off water getting rid of
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our body heat we can cool down while on the run and so our prey you know sprints away super fast
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but then they have to stop and cool down because death by heat stroke a terrible way to die and you
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know eventually we can catch up forcing them to sprint away and sprint away and sprint away until
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they're so weakened by heat stroke that you know they're easy to to kill or to hunt and what's so
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amazing about humans is our naked skin surface right so if you think about a dog panting we all know
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that's how dogs cool down it is evaporating away water because that's the best way to cool your body
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down but it's doing it off the only naked surface that it has its tongue right and instead humans have
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our whole bodies to do that on and even chimpanzees are our closest evolutionary neighbor or relative
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although they have sweat glands over their whole bodies many many primates do not all but some
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they are cooling down by panting because you know our naked bodies have that surface area and you know
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the modern incarnation of this is you know we can run marathons we're really good at you know not
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dying of heat stroke while we're exercising heavily yeah we uh had daniel lieberman on the podcast and i
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think you talked oh he's great yeah and he talked about there's they've done he's done a race with
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horses like so it's like a long distance race where he raced a horse and in the beginning the horse was
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beating him but eventually the humans all beat the horses because the humans can keep going because the
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horse at the stop because they overheat and they have to cool down exactly and what's kind of also amazing
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is that because this like evaporation of water is so important for staying cool animals dispatch other
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bodily fluids whatever they have available to the surface of their their bodies to get rid of heat
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and you know you know dogs use saliva but you know seals rely on urine honeybees vomit on themselves
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all to get their bodies wet so that it can away heat and the thing about humans is a we've got
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specialized glands just to do this number one and number two we do it so much more efficiently than
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than all other animals and so yeah it really is our kind of amazing evolutionary superpower and if you
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know what evolution could have bequeathed us like we could be cooling down from pee like would you know
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that sweat is so much less gross right yeah i'm grateful i don't have to pee myself to cool myself
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down so let's talk a little bit more about sweat so one of some of the research that's been going on
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is trying to figure out how soon does the water we consume become sweat and i think that also we
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need to ask too is like how often are we sweating are we sweating all the time or do we only sweat when
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we get you know reached a certain temperature right we are sweating all the time if we weren't
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we would be freaking miserable right our body's constantly making micro adjustments and most of
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the time when we notice sweat it's because we've you know upped our activity and so our sweat glands are
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like on hyperdrive and they're like crap we got to get going right but at any moment your body is
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releasing a tiny amount of sweat to make micro adjustments to your internal temperature and so
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you know as as a result we do need to drink water to stay hydrated and uh there's this awesome
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scientist that you're kind of referring to this guy named michael zek who really likes going to the
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sauna and uh one time he was like in the sauna getting philosophical with his buddy and they were like
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hmm you know i wonder how quickly you know when you drink a glass of water how quickly does that water
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you know get absorbed by your intestinal tract get you know put into your blood get dispatched to your
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you know internal organs percolate to your skin and then emerge out in sweat and you know when most of us
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get philosophical in the sauna you know that's the end of that but because he's a scientist he could do the
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experiment and so he spiked his favorite rehydration drink which in germany for him is this weird
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combination 50 50 cola 50 50 wheat beer it's kind of like a brown shandy and uh so he spiked it with
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this chemical that he could measure and that's not normally found in our bodies or in our sweat
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so he drinks his cola weizen it's what it's called and then quickly undresses gets into the sauna and starts
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measuring and capturing the sweat coming out of his skin at timed intervals and he found that
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it took 15 minutes for that chemical tracer that he had put in his drink to come out of his sweat
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pores which is pretty fast right that is really fast i didn't think it would be that fast
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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
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fast so sweats primarily to regulate our body temperature but we also sweat when we're anxious
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nervous why do we do that that's super interesting to me so there's like a lot of speculation about
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this one idea that uh researchers have is that it's kind of anticipatory right when we're anxious
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for most of human history we've had to like run really fast away from the thing that we're scared of
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and so it might be our body effectively predicting from anxiety that we're going to be running and thus
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turning up the heat and that it would be wise to perhaps start the cool down strategy pronto but
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it's also this really interesting kind of vestigial aspect of evolution so remember how i said humans
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have these salty sweat glands over our whole body we've got millions of them and what's really
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interesting is that all mammals have those salty sweat glands but they're only located for most mammals
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in their paws and that was because initially this eccrine sweat this kind of salty you know watery
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parts of blood was used for grip for climbing and effectively when an animal got scared and had to like
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run away possibly up a tree that's a little bit of that sweat would come out to help them with grip
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and so you know when you're stressed out and notice that your hands are getting sweaty it's a vestigial
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response um from you know your your mammalian predecessors that had to climb a tree in their anxious moments
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interesting so another thing you highlight too is sweat works better in certain climates than others and
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keeping it cool so the whole cooling mechanism is evaporation how does climate affect how effective
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that evaporation cooling is yeah so you know in a hot climate you can imagine the sweat is evaporated
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much more quickly away and that's due to some chemistry that you may have learned in high school
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like in a very humid place there's already a lot of evaporated water in the atmosphere and it's kind of
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giving a pushback to the water on your skin that's trying to evaporate to whisk away heat and so in a
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desert the water that you emit with sweat really evaporates quickly and so that's really good for
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cooling it's not good for for hydration that's why in many very dry climates you're advised to wear
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cool loose clothing so that you kind of keep a little bit of humidity at your skin surface right
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but in really super sweaty climates or humid climates sorry you want to take off as much clothing as
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possible to effectively give all those water molecules on your your skin a chance to to get
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out and away even when there's already a lot of water molecules around in the atmosphere kind of taking
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up space all right that's a good practical takeaway there keep me cool i live in oklahoma it's really
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humid here so wearing lots of loose clothing during the summer not probably a good idea
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but if i were in arizona yes yeah exactly and if you think about what a dog does while they're
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panting the whole reason that they're heaving in and out like the panting part right is they are
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trying to push all that water that is just evaporated up off their tongue and is making the surface just
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above their tongue dense with water molecules they're heaving all that wet air away and allowing
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drier air to come on top of their tongue to make more room for more water molecules so that's the
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whole point of panting is to kind of move that wet air away as fast as possible especially since
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they don't have a lot of surface area for this cooling strategy well let's talk about how sweating
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differs across populations so you you started this book because you thought well i'd probably sweat more
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than most people and you just told me you have three million sweat pores how what influences how much
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we sweat is it primarily genetics or can our environment also play a role yeah it's a bit of
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nature and nurture situation so certainly um some families are sweatier than others and that could be
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due to you know just the number of sweat pores that you have on your body there's quite a range also
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like the flux out of your sweat glands so how quickly the sweat is coming out that's a big range and
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your genetics might mean that you have a bigger flow than i do or i probably have a bigger flow than
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you and then there's also you know how quickly how responsive your body is to temperature changes
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but what's really interesting is this nurture side and evolutionary biologists are are really digging
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into this right now because when you're born you're born with all the sweat glands that you're
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gonna have like sweat glands are developed in utero but they don't all become active at birth it's only
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in your toddler years that like they come you know to become fully operational so to speak and so in
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those first early years of your life your body is cluing into the environment in which you live and
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and learning whether you know you're in a super hot place and so you have to maybe be a bit more
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active or more efficient or whether you're in a cool place and so yeah there's this mix of both you
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know what you have genetically and you know where you spent your early years i mean the take-home message
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though is that you can blame your parents for both because uh they're responsible for your genetics and
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you know also presumably where you spent your toddler years well let's say someone is born in a
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cool cold dry area and then they move to florida for example will their body adapt and sweat more or less
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based on that that move right so there your body's uh acclimatized right so you know but they do it a
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little bit slowly and then you have this like baseline which you start with so you know for example
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right now athletes are prepping for tokyo where it's super humid and super hot some say it might
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be the hottest olympics ever and so they are all training in extremely hot weather so that their
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bodies can figure out how to be efficient at cooling in extremely humid hot weather so you do there is this
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process where your body does learn to adapt but at some point we all have a baseline and that baseline is set
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in your your toddler years and so yeah you know there are some micro adjustments but um at some
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point you're stuck with what you have we're gonna take a quick break for your words from our sponsors
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and now back to the show something i've read i don't know where i read it maybe on the interwebs or
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on like in a men's health magazine from 1992 or something uh is that the fitter you are the more
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you sweat is there anything to that well yeah because if you are super fit right your body has
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learned that when you start exercising when you start dialing up the temperature you are not going
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to be doing this for you know 30 seconds or even you know 15 minutes you're probably going to be doing
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this for like over an hour and so athletes actually have a tendency to sweat more the more that they train
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and the and the fitter that they are and this is also true for people who kind of have sauna going
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as as a hobby so for example i noticed that when i moved to germany and you know wanted to you know
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integrate with the locals who are all obsessed with going to to the sauna that my sweating rates got
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faster and more voluminous because i was suddenly going to the sauna not just for you know a one-time deal
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but like going regularly and spending a heck of a lot of time in a really hot space so ultimately
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it's all part of this like acclimatization process where your body is like learning about your behavior
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and figures out that oh geez when the temperature rises she's going to be in there or he's going to
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be in there for a heck of a long time let's get cracking on the cool down directive are there
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differences between men and women and how they sweat not really so generally uh any differences
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that you see are most likely just due to volume to surface area issues there's not anything really
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biologically different in how sweat glands work or or how many there are but because you know men are
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on average larger than women they've got slightly more sweaty activity because they've got that much more
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body to keep cool well let's get to the fun stuff here which is like why sweat smells and like the social
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aspect of being smelly humans so you mentioned earlier that one type of sweat forgot the name of the gland
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the sweat pore that produces starts with an a right oh apocrine yeah the apocrine sweat that's the stuff
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so the bacteria on our skin and our armpits starts eating that stuff and the bacteria fart and that's
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basically our bo why do i guess i would say i think americans or westerners in general like why do we
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find bo so off-putting like why don't we like it well so i would say two things i think that americans
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take it to a whole nother level of of insecurity but i would say that for much of human history people
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have been kind of worried about the odor of themselves so one of my favorite quotes which is on my wall right
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now it's advice from the roman poet catullus so literally like two thousand years ago um to his
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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
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choice silk or the enticement of a pellucid gem you're being hurt by an ugly rumor which asserts that
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beneath your armpits dwells a ferocious goat this they fear and no wonder for it's a right-ranked
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beast that no pretty girl will go to bed with so either get rid of this painful affront to the
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nostrils or cease to wonder why the ladies flee so i love that because you know it speaks to the fact
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that you know for at least two thousand years we've been a bit worried about our body odor but most of
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that time the way that we've dealt with it is to wash with water possibly soap and or apply a huge
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amount of perfume to kind of overwhelm our bo and it wasn't really until the turn of the 20th century
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when what we you know use now deodorant and antiperspirants get invented and so up until this
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point people have a background body odor of of each other they know each other's body odor really
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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
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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
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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
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invented this thing called whisper copy which puts the fear of stink in humans and you know in the
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1919s they started their advertising strategies towards women and then they started trying to convince
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women to buy deodorants and antiperspirants by saying listen you know if if you sweat you stink
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and people are talking about you behind your back and not only is this gossip hurting your reputation
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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
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1930s when they've you know got the fear of stinking so many women that they've maxed out the the market
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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
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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
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rely on this thing called whisper copy right putting social fears of exclusion in men but instead of
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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
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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
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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
00:26:47.740
coming off of an armpit and they have actually found what's known as two top notes um and one
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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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
00:47:49.800
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00:47:53.140
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00:48:21.480
reminding you to not only listen to the aom podcast but put what you've heard into action