Why do people have physiologically different tolerances to high/low temperature extremes?

I’m actually looking for a factual answer (if there is one) - thyroid function? Metabolism? Acclimation? Gender?

I live in a state with four seasons - it can be hot and muggy in summer, and bitterly cold in winter. In hot, humid weather (and for me “hot” is anything much over 75 F, depending on humidity) I am enervated and very unhappy. However, I’m very tolerant of cold weather. Like it, can go for long walks in below-freezing temps as long as I’m dressed sensibly, etc.

A good friend is the polar (heh) opposite. When it’s what I would call pleasantly cool and I’m in shorts and a tee shirt, she is bundled in long pants and a sweat shirt…she will be shivering with goose pimples. If it’s cold out, we can spend the same amount of time outside and her ears and other extremities will be chilled and cold to the touch, while mine are warm. When it’s hot, she appears quite comfortable, while I am red-faced and sweaty with the slightest exertion. I don’t think it’s acclimation, because we’ve both lived in places with temperature extremes for decades. We are both pretty skinny - I’ve never noticed a weight trend in people I know being intolerant of temperature one way or the other.

I’ve wondered whether hormones or thyroid function has anything to do with it - I’m post menopause and have noticed a definite increase in my dislike of hot muggy weather in recent years.

Well, of course metabolism has an effect, as does age, general health, fitness, level, and so forth. Some problems, such as thyroid disorders, can definitely be a factor. Circulatory efficiency is another one - people with poor circulation in their extremities may well have difficulty tolerating cold temperatures, as an example.

There are also two other forms of adaptation at work as well.

The first is genetic adaptation. Various populations have spent many generations living in the arctic or the tropics or other types of environments and over many generations some small genetic tendencies have propagated through the populations. Hence, dark skin in areas with a lot of UV, but also differences in extremity size (arctic populations tend toward, proportionally shorter digits and limbs than tropical ones) and probably some metabolic differences. These are, it must be emphasized, subtle - people of tropical descent have moved to arctic locales and thrived and vice versa. They may, however, be sufficient to lead one to favor warm vs. cool situations when factored in with everything else.

The second type is individual adaptation - where and individual’s body and metabolism undergoes some changes in response to the environment, making that person either more cold or heat tolerant. This generally takes a couple weeks of being in the environment, and get result in the body increasing metabolic rate to maintain body warmth in cold environments, or tweaking cooling mechanisms in hot ones. With modern indoor climate control some people may be maintaining either summer or winter conditions all year round in their home, leading to less shifting in response to the actual weather.

body size and composition is a factor.

thinner or smaller people get rid of heat more rapidly.

Hadn’t thought about racial/genetic differences - a very fast google does suggest that factor is indeed subtle and quite attenuated.

My sample size of two people in my anecdote - we are both fairly small and thin (and female and white), yet one of us is very heat-tolerant, the other very cold-tolerant. On further thought, two other people I know well IRL who don’t do at all well with cold weather but love heat are quite fat.

I’m finding it difficult to find definitive answers online! Apparently the three glands that control a person’s temperature regulation are the hypothalmus, the pituitary gland, and the thyroid gland. I’m suspecting there isn’t one definitive answer, but rather it’s a complex interplay of different physiological functions and adaptations…

It seems like in my office building, people fall into two camps: the ones who think it’s too cold and the ones who think it’s too hot.

Almost everyone in the first group is female. Particularly pre-menopausal female. Fat, skinny, in between. It doesn’t matter. We’re always cold. The women are walking around in sweaters and gloves, while the guys are laughing at us and telling us we’re being silly (which drives me crazy, but I digress).

I have sat at my desk literally shivering while the guy out in the cubicle outside my office has a fan blowing on him.

My guess is that the explanation can be attributed to the differences in body muscle percentage between the sexes.

Interesting, I do have an unusually high percentage of body muscle for a female. But I’m not sure that’s really a factor - to add to the battling anecdotes, most women I know (in my age range) actually are in the “it’s too hot” camp
regardless of body weight and most of them are over, rather than under-weight.

When I was going through the roasting over-heated hell that can be menopause and was living with a man, we compromised a lot. He had the down comforter, I had the windows open (In Michigan. In January.) I would literally go open the freezer and stick my head in there to cool off. Or walk outside practically naked in mid-winter in the middle of the night to cool off because everything, everywhere, was too hot.

But I haven’t had a hot flash in years; I’m referring mainly to day-to-day temperature tolerances.

As I grow older, I have much less tolerance for cold, and much more for heat. I understand that that is typical. My AC is set on 85, and the heat index outside is 107, and my oven is on, cooking a pot roast. I feel fine.

It might be, though - muscle has a higher metabolic rate than many other tissues. It might be that even at rest you’re generating body heat more efficiently than a woman your size and age with less skeletal muscle.

If you want another data point: I used to be extremely cold tolerant and fat. Then I went on a major diet (lost 70 pounds, have stayed in the ‘normal’ weight range for years) and ever since I cannot tolerate cold at all. As in, I’ll wear two layers of sweatshirts in the house when my husband (and visitors) say they are perfectly comfortable.

OTOH, I no longer mind summer heat. In fact, I can exercise outside in 90 degree plus temperature and hardly sweat.

But whether this is due to the loss of insulating fat OR my metabolism having downshifted now it doesn’t need to burn nearly as many calories per day to maintain my weight, who knows? Actually, could very well involve both.

Seven years ago I moved from Holland to Spain. In The Hague, right next to the sea, humidity tends to be rather high but it rarely gets very hot. However, I’d start to get uncomfortable at about 25 degrees. In Madrid, on the other hand, humidity is quite low and although it gets pretty cold in the winter, the summers are very hot. But 30 degrees in Madrid never felt like a big deal, only at 35 or above I would be really uncomfortable. (Not helped by my thoughts that above 37 degrees YOU DIE WHEN YOU STOP SWEATING. But don’t worry—you don’t stop sweating!) Also, after that first summer I got a lot more heat-tolerant.

Interestingly, I never have much trouble with cold weather outside, but I can get pretty cold inside. Being on the move (walking/cycling) vs sitting on the couch makes a huge difference. I also notice that my tolerance for cold varies throughout the day. In the evening I first get cold but then around bed time I start getting warmer.

Feeling hot vs cold also seems to be related to weight, as lots of people report being cold as they lost weight. I lost quite a bit myself the past year and a half, but I haven’t really noticed much of a difference. I’m thinking it’s probably not just the insulating properties of the fat, but also the fact that heavy people usually have an energy surplus so their bodies will burn off the extra calories while people who are/have been losing weight operate under an energy deficit so their bodies will probably want to conserve calories rather than generate extra heat to compensate for a colder environment.

Maybe this explains why women tend to feel colder than men, presumably more women are dieting than men. Ironically, women’s clothes tend to expose more skin, not helping the situation.

One thing that has puzzled me over the years is how often the people who complain that it’s too cold when the AC is set at 78 in the summer are the same ones who complain it’s too hot when the heat is set at 68 in the winter.

Does the temperature stay the same, though? More than once I’ve lived in places where I could tell whether my neighbors were in or not by how warm my own flat was. In the winter I keep my thermostat at 17ºC most of the time, raising it to 20ºC when I’m going to be moving around the house (no A/C, so if it’s hot the 'stat is just a wall decoration); when the downstairs neighbor aka Mr I Walk Around In My Underpants is in, my own heating doesn’t get triggered at all; the side neighbors prevent part of the lower-temperature triggers but it will still trigger occasionally and it will trigger normally when I raise it.

your body also adjusts seasonally if needed. if you have colder and warmer seasons then your metabolism shifts to cope.

You wear different clothes in the summer than in the winter. If it’s a 90 degree day out and I’m wearing shorts and a t-shirt, being inside in AC will feel cold. But if it’s winter and I’m wearing a turtleneck sweater, it could feel blazingly hot inside a place with the heat on.

And yeah, I’m another one who is always cold when others (usually men) are hot. Being a slender female will do that.

I’m guessing yes, because I’ve observed the phenomenon too consistently, but I need to invest in a thermometer to find out for sure.

My wife can go out in 98 degree weather and not break a sweat. Heat doesn’t bother me quite as much as it used to, but I still don’t like it.

Surface area increases as a square, while volume increases as a cube. So bigger means relatively less surface to radiate heat (and lose thru convection and conduction) than smaller has.

A professor of mine in college read us “Horton Hears a Who” and pointed out that the illustrations were physiologically correct - the Whos who are small are covered with hair, while Horton the elephant is relatively naked. Hortons’ problem is keeping cool, the Who’s problem is keeping warm.

I can still remember that lecture. Two memorable phrases - “Don’t talk to me about the lilies of the field - Solomon in all his glory never fixed a glucose molecule in his life”, and, of course,

Regards,
Shodan

That’s only relevant if the amount of energy used for body heat is constant. And it isn’t, because mammals of all sizes manage to keep a stable body temperature. Small mammals just have to burn more energy per unit of volume than large ones to accomplish this.

And what we’re talking about is not actual heat loss, but rather the subjective of being warm or being cold.

But I’m talking about workplaces where people dress the same throughout the year.

I don’t know what the mechanism is for implementing various temperature tolerances (though apparently they include degree of vascularization of the extremities and onset of muscle contractions around whatever hair is there).

But an earlier level of “why” is more specifically “why would evolution have settled on variability in temperature tolerance?”

It seems like there would be evolutionary advantage in variability, because when conditions change (perhaps if there are some extreme weather years), odds are that some will be much better suited to the new conditions than average. Occasionally, the people who are extreme (in whatever relevant way) are the ones who will live to carry on the species.