19 hours ago
Hot and bothered? Science explains why some people melt in the heat — and others don't
PARIS, June 29 — When summer temperatures rise, not everyone handles the heat in the same way. Some people breeze through scorching days, while others seem to wilt in the warmth. What lies behind these different coping abilities? The answer can be found in a combination of physical traits, genetic influences and behavioural habits
When the warm weather arrives, two distinct camps emerge: those who love the heat and those who hate it. And each tribe has its own rituals and interests. The former dream all year round of jetting off to sun-soaked destinations, while the latter head for northern climes to avoid scorching temperatures.
A matter of taste, some would say. But also of physical constitution. Indeed, we're not all equal when it comes to the summer heat. Some people tolerate it less well than others, whether it's a dry or humid kind of heat. These inequalities depend on a number of factors, including age, gender, build and hormonal balance.
Human beings are 'homeothermic' animals, meaning that we keep our core temperature relatively constant despite any changes in the surrounding conditions. But, at the same time, our bodies naturally produce heat, which also makes us 'endothermic' creatures, like other mammals. When our bodies are exposed to intense heat, they thermoregulate by producing sweat. It is the evaporation of this sweat through the pores of the skin that evacuates the heat, thus lowering the body's temperature.
Biological inequalities
But this internal climate-control system doesn't work in the same way for everyone. Babies and older people sweat less than adults, which explains why they are so sensitive to ambient heat. They are also more likely to suffer from dehydration, as they don't tend to feel as thirsty. Yet the body needs a sufficient supply of water to produce sweat and adjust its core temperature.
In addition to age, our ability to withstand high temperatures depends on our biological sex. The assumption that women are more sensitive to heat than men is confirmed by numerous scientific studies. Research from the Netherlands, published in 2021 in the journal International Archives of Occupational and Environmental Health, reports that deaths during heatwaves are higher among women than men.
These differences are due to a number of possible causes, including differences in height, weight, perspiration, cardiovascular strain and hormones. However, it would be wrong to say that women's greater discomfort in summer is solely linked to biology. It also stems from social factors, with the Dutch researchers explaining that women are less likely than men to be well-equipped to cope with the heat due to income inequalities.
Changing behaviour to better tolerate heat
In addition to the physical differences between individuals, heat tolerance is closely linked to lifestyle. When temperatures rise, many people turn on the air conditioning. And this may be a good idea in the heat of the moment, but it can be less so in the longer term. The stronger the air conditioning, the greater the difference with the outside temperature. This puts our bodies to the test when we leave the air-conditioned space. Too severe a change in temperature (over 10°C) can lead to thermal shock, and in the worst case, loss of consciousness or even cardiac arrest. So it's best to use air conditioners sparingly.
Diet also has an impact on our tolerance to high temperatures. Fatty or high-protein foods contain compounds that are relatively difficult to digest. Our bodies have to expend more energy to process them, and therefore generate more heat. That's why we often sweat profusely after eating sausages, burgers and other grilled meats at a barbecue. When the mercury rises, opt for light meals with vegetables, lean meats or fish. Similarly, it's important to limit alcohol consumption.
Generally speaking, it's perfectly possible to change your habits to acclimatise better to the heat. And that's good news as the effects of global warming become more keenly felt. Over the period of February 2023 to January 2024, the global surface air temperature was 1.52°C higher compared to pre-industrial levels of 1850-1900, according to the EU's Copernicus monitoring programme. In this context, we're going to have to be adaptable if we're to learn to live in a world where our tolerance to heat will be increasingly challenged. — ETX Studio
