Sweat Glands - Activate!

November 30, 2018 11:21 PM

Have you wondered why people from hot climates can handle the heat better than those from cold climates? In the December 1991 issue of Natural History, Jared Diamond wrote the article "Pearl Harbor and Emperor's Physiologists" with the subtitle: Our ability to feel comfortable in hot climates depends on where we spend the first few years of of childhood.
posted by ShooBoo (27 comments total)

Asians have more sweat glands.
posted by Tarn at 12:26 AM on December 1, 2018

(FYI for others: this is a link to a scan of the magazine article from the internet archive, it's not fantastically readable, unfortunately).
posted by smoke at 2:08 AM on December 1, 2018 [3 favorites]

Even before the addition of Hokkaido (right under Sakhalin) to the north and Okinawa (right next to Taiwan) to the south in the Meiji era, climate in the core islands of Japan goes from warm in Kyushu to freezing in Tohoku. A good chunk of Honshu isn't called "Snow Country" for nothing. OTOH, Kyoto is famously sweltering in the summer because the mountains around it concentrate the heat and stop cooling winds.

So, eh, you'd expect some variation in Japanese people's capacity for acclimating instead of treating the Japanese as homogeneous but I'm sure believing in the homogeneity of Japanese people can't have a political origin.
posted by sukeban at 4:32 AM on December 1, 2018 [9 favorites]

Jared Diamond on metafilter previously.

Environmental determinism is bullshit that Diamond has spent his career peddling.
posted by medusa at 5:22 AM on December 1, 2018 [28 favorites]

Yeah, pretty much. As appealing as his theories are, they're mostly just him sitting and thinking about issues and not actually supported by any real science.
posted by hippybear at 5:46 AM on December 1, 2018

That's the problem when ornithologists try to put together Grand Theories of human culture and evolution.
posted by ChuraChura at 5:52 AM on December 1, 2018 [8 favorites]

I was born in a sweltering delta and grew up in the tropics. In my mid forties I moved to within a few hundred miles of the Arctic circle. Its taken a couple/three years but I've adapted to the cold as well as possible and shed downpours of sweat for the first 24 hours whenever I return for a visit as my body adapts. Last week I was in tshirts while my family around me were in sweaters in a third location with a milder winter. My adaptation to the Arctic was rather obvious. My own experience tells me that the human body is an extremely adaptable flexible organic thing of beauty.
posted by infini at 5:55 AM on December 1, 2018 [11 favorites]

I also hate the stupid research outputs that claim heat makes you stupid. Those acclimatized to that heat aren't stupid though those coming directly in from temperate climes may feel stupid. All of these are related to the colonial era thinking of fatalistic Hindus lying around in the heat unable to administer their country.
posted by infini at 5:57 AM on December 1, 2018 [14 favorites]

For what it's worth, I've done some casual surveying about heat/cold tolerance, and it doesn't seem to corelate with much of anything.

I've been told that the US military tried to find a pattern, but couldn't find a better method than asking people about how heat and cold affected them.
posted by Nancy Lebovitz at 6:01 AM on December 1, 2018 [5 favorites]

My partner and I grew up in the same city at the same time. Our thermostat would beg to differ.
posted by evidenceofabsence at 6:07 AM on December 1, 2018 [13 favorites]

There are a few studies suggesting that childhood sun exposure modulates the risk of getting multiple sclerosis. No-one is sure about the mechanism though.
posted by Vortisaur at 6:39 AM on December 1, 2018 [1 favorite]

As a Canadian I have to constantly tell people from other countries that we are adapted to cold winters through an unexpected mechanism.

We dress properly for it.
posted by srboisvert at 7:21 AM on December 1, 2018 [28 favorites]

I got distracted paging through the magazine scan to look at the ads! Wow was it a different time. It's like the magazines from 1996 in my doctor's waiting room except a lot less Gwyneth Paltrow/Brad Pitt drama (they dated back then!) and a lot more casual racism.

Like, a lot more. The linked article is teeth-grindy already, but FYI - if you click one page too far, the article after Jared Diamond's is called "The Smoking Gun of Eugenics" and concludes with a false equivalence that being wrong about smoking and cancer is worse than being very sincere about eugenics, which, yikes. Be careful with your click speed if that's not something you want to stumble into.
posted by E. Whitehall at 7:38 AM on December 1, 2018 [1 favorite]

Ugh, him. Every time I see his name I think of that clip of him I saw years ago where he took a starving child's hand and burst into tears. I've never been sure if that was spontaneous or for the camera. My suspicion that it's the latter has stayed with me ever since.

I probably shouldn't be surprised that the article was even allowed in a publication like that, but I am. It reads like any column in the Psychology Today mags that lay around in my therapist's reception area. I expected their journal to be a little more academically rigorous.

I don't know about any mechanisms about adapting to heat or cold. I much prefer cold weather, but have no idea why. I was born and raised in cold places, but I don't think that means anything.
posted by droplet at 7:50 AM on December 1, 2018

born and raised in the suburbs of Toronto (with a sidetrack to Ireland when I was almost three). So what does that equal? Hot humid summers, cold winters, perpetual damp with no central heating (Ireland) -- not exactly tropical, I guess. And when I have been to the tropics (or when the tropics come to me in the form of a proper heatwave like we got for over a month last summer), well, yeah, that heat is a bastard ... until I sort of surrender to it. Hydrate properly, get used to sweating a lot, napping during the hottest part of the day, adjusting my diet. So label me undecided on this.

The biological determinism I do buy is along the lines of people who've lived their lives at high altitudes not doing so well at sea level (and vice versa) because of how one's lung capacity has developed.
posted by philip-random at 9:43 AM on December 1, 2018

Came here to dunk on Jared Diamond, saw that it had already been covered. I swear, that man is only famous because he has a memorable name. I wish he would just be quiet already.
posted by Anticipation Of A New Lover's Arrival, The at 9:52 AM on December 1, 2018 [1 favorite]

Give him a break, Collapse made me cry. If it had made a bunch more people cry, we might still have a planet with a future instead of the profitable mess ongoing right now.
posted by infini at 10:06 AM on December 1, 2018 [2 favorites]

Unfortunately, a lot of the stories in Collapse are just ... not true, not accurate, and/or not supported by the archaeological and ethnographic evidence. He's good at telling Just So stories.
posted by ChuraChura at 10:51 AM on December 1, 2018 [8 favorites]

Rather than link to the (paywalled) research itself, there was just a decent article in the Atlantic which covered some of the research on adaptability to cold in people, which suggests that long-term genetic changes to uptake of thyroid hormones occurs in people in colder climates, which affects their basal metabolic rates and causes their metabolic rates to be higher than those who live in lower, hotter latitudes. Which of course suggests that lower metabolic rates might have something to do with heat tolerance. But it appears that this is one of the areas of medicine which has a lot of work to do? (Serious question, I don't know.) Adaptability to heat and cold could also differ significantly with changes in humidity, which must make the problem even harder to study? But I find it fascinating from an evolutionary standpoint that chemical changes in the body affect the situation, because that makes it much more than a simple surface area to volume ratio problem (Bergmann's "rule"*) when examining humans and other species.

One idea I have truly enjoyed in recent years is the idea that humans' ability to thermoregulate our body temperature is what truly makes us exceptionable compared to other species. I don't know where that theory is going in terms of validity, but I delight in anything that challenges the idea that its our brains/thumbs/walking abilities that brought us to our current evolutionary state, because IMHO there's a certain amount of hubris/arrogance involved in studying ourselves. So I like the idea that we swapped panting for sweating and as a result may now have language, or that we became better walkers because we evolved sweating at the same time, or wherever the different theories may lead us in terms of first this, then that, or concurrent changes, etc. (Those are just hypothetical examples.)

Whatever comes about in terms of studying this, it is quite clear that climate change, and heat stress in particular, affected our evolutionary path. Of course, the snarky cynic in me wants to point out that with climate change, the very kinds of people that those who deny climate change (doing something about it) also tend to hate might turn out to be a lot more adaptable to it.

There's a lot to figure out! I'm really envious of all the physiological researchers out there right now, because with all the recent new knowledge about neurotransmitters, the brain/gut connection, gut bacteria, and all the other cross-disciplinary opportunities, the science behind how our bodies work and evolved just seems really exciting and brimming with all kinds of possibility and new things to learn and new theories to test. So neat there's so much we don't know! Those lucky scientists! Yay for them!

That's the problem when ornithologists try to put together Grand Theories of human culture and evolution.

ChuraChura, can I have your permission to put your awesome comment on a t-shirt and wear it to a vertebrate paleontologists/evolutionary biologists conference

*Like many others, I have problems with biological "rules" (like Bergmann's and Cope's) concerning size, but they're still around.
posted by barchan at 11:05 AM on December 1, 2018 [5 favorites]

We dress properly for it.

Being a US-born-and-raised person who spent about four years in Canada (in Fort Frances, just across the Ontario border from Minnesota, so close to not "really" Canada, although compared to southern Ontario, it's really Canada) I find that many Canadians seem to actually be acclimatized to it as opposed to dressing for it. Yes, when it hits -40, they dress for it for the most part. But anything less than that still has people running in light jackets without hats or gloves, and I saw shorts during winter more in Fort Frances than while I lived in Cleveland, Ohio, where it's significantly warmer.
posted by tubedogg at 12:17 PM on December 1, 2018

Running generates huge amounts of body heat. In the winter, when I'm hiking uphill and maxxing out my aerobic capacity, I'm usually wearing just my undershirt. No gloves, no hat. My legs and feet often get too hot because I can't shed as many layers down there so the bottom half is a compromise between what's comfortable when I'm climbing and what's safe when I'm hanging out on a frosty mountaintop in 40mph winds. Running is the same way—you end up wearing as little as possible just to avoid sweating. Your body moves all that hot blood to your extremeties in order to cool it down, so your hands and nose and such don't really get cold. It has to be very cold indeed (and usually windy too) before your body's ability to heat itself gets overwhelmed. I've seen winter trailrunners tooling up and down snowy mountainsides in jogging shorts and tank tops. As long as they keep moving, they're fine.
posted by Anticipation Of A New Lover's Arrival, The at 12:30 PM on December 1, 2018

One idea I have truly enjoyed in recent years is the idea that humans' ability to thermoregulate our body temperature is what truly makes us exceptionable compared to other species

This is definitely sort of true when it comes to aerobic exercise and thermoregulation - there's basically no animals on earth that can run as long as we can without overheating - Here's an article about elite runners trying to outrun pronghorns to prove this theory.

It has to be very cold indeed (and usually windy too) before your body's ability to heat itself gets overwhelmed

Yes and no to this one. Because of the running industry we actually have a really great insight into what the "optimal" temperature to run is:

When French researchers analyzed the finishing times of 1.8 million marathoners over a 10-year period, they found that a race-day temp of 43.2°F produced the quickest times overall. But faster runners, who generate more heat, benefited from cooler temps, with the top one percent (green line below) peaking at 38.9°F. Midpackers (red line) do best in the mid-40s.

Colder than this, and our bodies can still run and run well, but we're wasting energy on staying warm.
posted by smoke at 1:00 PM on December 1, 2018 [1 favorite]

i grew up with nyc's muggy summers; one of my best friends grew up near hue in vietnam. both of us laugh at the "if you grow up with it, you'll be comfortable in it" just so story.

hot humid summers are miserable and sucktastic.
posted by zippy at 1:54 PM on December 1, 2018 [4 favorites]

I'm relieved everyone is calling BS on this, because my anecdotal evidence is that my dad grew up without air conditioning in a city that averages a high of 115 deg F during high summer and he cannot handle the heat at all.

(Also I grew up in the deep South, and I'm a miserable, sweaty mess with frizzy hair and chafed thighs in extreme heat. No thanks!)
posted by grandiloquiet at 2:59 PM on December 1, 2018

I was born and grew up in Sydney, Australia. I function best when under 20C, and get positively cheerful when it gets below 10C, often in shirtsleeves. I've not yet had the chance to prove it, but I suspect - given a hat and sensible shoes - that a proper North American winter would be perfectly fine also, although perhaps swapping the shirtsleeves for something a tad heavier.

If anyone would like to swap Christmases, please let me know - I'm happy to supply all the 50+ sunblock you'll need.
posted by ninazer0 at 11:45 PM on December 1, 2018

Colder than this, and our bodies can still run and run well, but we're wasting energy on staying warm.

Anticipation, this is why you don't see shorts/tshirt runners here in HEL. The regular runners I see all have full bodysuits on.
posted by infini at 12:45 AM on December 2, 2018

What is the current understanding of sweat glands maturing? Because I've had that "heat encourages more of them to mature in children" factoid in my head for a couple years now. I found a few papers that reference the Japanese research about the total number of glands being formed at birth, but not much about what affects them after that.
posted by lucidium at 5:39 AM on December 3, 2018