The fact that there must be warm-blooded and cold-blooded animals among humans – spring brings it to light. While some are cycling around with their arms and legs exposed, others are still wrapped up in their winter coats. It is supposedly common knowledge that women are more likely to wear winter coats in spring and that their feet are constantly cold until May anyway.
It is all the more surprising that researchers at the National Institutes of Health (NIH) in the USA now claim to have discovered that women are more likely to be of the “Arctic type” compared to men: Your internal heating only starts when the outside temperature is one degree lowerthe researchers report in the journal PNASafter exposing 28 volunteers to temperatures between 17 and 31 degrees Celsius and measuring their energy metabolism.
So, contrary to all common wisdom, are women the ones who freeze less than men? The reason for the surprise discovery could be hormones, says Martin Reincke, director of endocrinology at the University of Munich Hospital. The women examined in the NIH study either took the birth control pill or were examined in the first half of their cycle. “In the second half of the cycle, however, the heat production in the body changes and women become more sensitive to cold,” says Reincke.
In other studies, the everyday perception has been confirmed: So Women in a Rotterdam experiment started shaking on average at 11.3 degrees Celsiusto keep warm – men only at 9.6 degrees. And while women felt uncomfortable below 18.3 degrees, men only felt cold below 14.6 degrees. Apart from hormones, women’s freezing is primarily explained by the fact that they have fewer muscles – because they are the most important heat factory in the body.
When things get hot, women have an advantage
“The lower muscle mass means that women have a lower basal metabolic rate even at rest and therefore also lower heat production per kilo of body weight,” says sports medicine specialist Pericles Simon from the University of Mainz. As a result, women would perceive cooler temperatures as colder even at rest more quickly than men. During physical exertion the difference becomes even greater. In addition, women have around 15 percent thinner skin, which means they cool down more quickly. Because women are lighter than men despite being the same size, their body surface area is relatively large, which means that more heat is lost.
The frequent shivering also has positive sides for women, because it means they are essentially in energy-saving mode. “This helps the woman to maintain her energy reserves for longer,” says Pericles Simon. On extremely long running distances, women are almost as fast as men, and the gender gap is shrinking. Women also perform at higher temperatures significantly better mental performance than men, as researchers from Berlin and Los Angeles showed a few years ago. In order to think better in summer, you can also accept cold feet in winter.