2024-11-21 08:15:00
The energy crisis and calls for sobriety for the winter of 2022-2023 have brought the debate on comfort temperature to the fore. While the government invites, from the beginning of the school year, not to exceed 19°C in offices and homes, everyone is reminded of the obvious: we are not all the same during periods of low temperatures.
The intuition that women are more sensitive to cold than men is in fact confirmed by numerous scientific studies. The ideal environmental temperature is, according to various research, between 22°C and 24°C for men compared to 24.5°C and 26°C for women. If the data differ, the observation remains the same: there would be approximately two degrees of difference in comfort between the two sexes.
Male hormones inhibit the sensation of cold
These inequalities of feelings depend on multiple factors, such as age, state of stress, tiredness, metabolism and hormonal state, explains Dimitra Gkika, professor of physiology at the University of Lille.
Thermogenesis (mechanism of increasing internal temperature) and thermosensation (sensation of external temperature) can therefore both fluctuate under the influence of hormones. “We did it the experiment on mice and rats, says the researcher. When we took away testosterone, through castration, the males became more cautious. And when we gave them testosterone again, they recovered the initial thermosensation: they were less sensitive to cold. »
Testosterone inhibits the TRPM8 channel protein that senses environmental cold through nerve terminals under the skin
Scientists have shown that testosterone inhibits the TRPM8 channel protein which <a href="https://www.sci
In contrast, in women, estrogen significantly thickens the blood, which does not flow as easily to the extremities. A study from the University of Utah demonstrated, in 1998, that hand temperatures were 1.6°C lower in women than in men. Estrogens also influences on the suprachiasmatic nucleus, a part of the hypothalamus that controls thermoregulation.
Also, the release of progesterone during ovulation contributes to heating internal temperature of the order of 0.3°C to 0.7°Cmaking women’s bodies more sensitive to external cold. A similar phenomenon is observed in women who use the contraceptive pill.
Adipose layer, muscle mass and metabolism
There are also mechanical explanations for this difference in sensitivity: muscle masses (which generate heat) and fat masses (which do not generate it) influence the sensation of temperature. But women have on average less muscle mass. On the contrary, the adipose layer that separates the muscles from the skin, naturally colder, it is more often in women.
Even the female metabolic rate, i.e. the amount of energy burned by the body at rest, is lower than the male one below 20°C. a 2021 Chinese study noted. Many
This propensity of female individuals to find comfort in a warmer atmosphere than their male counterparts could be explained by evolutionary biology. This discrepancy is found in many endothermic (producing their own body heat) birds and mammals, he notes a 2011 Israeli zoological study.
Among various hypotheses, the authors propose that females have a greater need to protect newborns from low temperatures, and that natural evolution has favored females who are less capable of endangering their young by exposing them to too cold temperatures.
Thermal standards to be reviewed
However, be careful not to reduce the alleged female reluctance to a purely biological issue. The more pronounced discomfort of women in winter also derives from social choices, in particular from the thermal standards designed by men for men.
Dutch researchers did it observed in 2015 that the most common air conditioning devices have as their target a man in his forties, weighing around 70 kg. “This overestimates women’s metabolic rate by an average of 20% to 30%.”explained to Telegraph one of the study’s authors, Boris Kingma, from Maastricht University Medical Center, the Netherlands.
“The current concept of thermal comfort is focused on humans, but in science it is a more general problem,” explains Dr. Gkika
Therefore, the ideal temperature in offices is arbitrarily set between 20°C and 21°C, while for women it would be around 25°C. The authors called for a new system to calculate thermal comfort that takes into account differences between sexes, but also age and physiological characteristics, such as thinness or obesity.
“The current concept of thermal comfort is human-centric, but in science it is a more general problemobserves Dimitra Gkika. In many studies, for example to develop drugs, the tests are based on the male body. But in recent years the scientific community seems to have become aware of this problem. »
Does the comfort gap between men and women mean it’s impossible to find a temperature that works for everyone? Not necessarily.In 1972, three Scandinavian researchers carried out the experiment a study in two classes of high schools. “For a mixed population, the “optimal” temperature is one in which the proportion of girls who are too cold equals the proportion of boys who are too hot.” they explained. “This point in the current data is 24.3°C, a temperature at which 16% of girls were too cold and 16% of boys were too hot.” concluded the experiment. The scientists also pointed out that it is easier to get dressed when it’s cold than to take off your clothes if it’s too hot.
What are the key factors influencing thermal comfort in shared environments?
Kika, an expert in the field. The need for a more inclusive framework is increasingly recognized as essential for improving comfort in shared environments, such as workplaces and public spaces.
An evolving understanding of these dynamics acknowledges that women may require significantly warmer conditions than men, potentially leading to discomfort and decreased productivity in environments where temperature settings are based solely on male physiological metrics. Consequently, researchers are advocating for adjustments in climate control standards that integrate a more comprehensive picture of human diversity, including gender, age, and body composition.
By re-evaluating thermal comfort standards, we can create healthier and more equitable environments for everyone, ultimately enhancing well-being and productivity for all individuals, regardless of their physiological differences.
As this conversation around thermal comfort continues, it highlights the broader implications of how scientific research informs public policy and environmental design, emphasizing a shift towards inclusivity and responsiveness to the diverse needs of the population.