Why are we unequal in the face of the cold?

He is constantly in a T-shirt, even when it’s freezing. She puts on a wool sweater as soon as the first cold weather arrives! Why this injustice? This inescapable debate of the difference in resistance to cold is not new. In question ? In the face of the cold, man and woman are not equal.

Did you know that the internal temperature in a man or a woman is not the same? In a man, the internal temperature is around 22 degrees, while that of a woman is between 24 and 25 degrees. Hormones also get involved: estrogen in women prevents proper circulation to the extremities of the body. While in men, testosterone makes it easier to withstand temperature drops.

The other reason for this difference in cold hardiness, according to Swedish researchers from the Karolinska Institute, is the presence or absence of a protein in the muscles of the body. This protein, called “α-actinin-3” influences the feeling of cold. Those who do not have this protein in the muscles are more resistant to cold. Nearly 1.5 billion do not have this protein in their body.

Thanks to it, the muscles have more fast-twitch muscle fibers. But faced with the cold, the fibers contract several times and quickly: which wastes a lot of energy. Admittedly, these people perform well in sports requiring rapid and intense effort, but they are less resistant to the cold. While people who lack the protein “α-actinin-3” have slow-twitch muscle fibers, therefore expend less energy and retain more body heat. They are more durable in the long term!

This inequality of resistance to cold is not about to change! And the eternal debate to know whether to increase or lower the heating in a room will for a long time be the subject of disputes within a couple…

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