It’s going to be cold, very cold. Up to -10 or even -15°C are expected in places in the coming days, with the arrival of icy air over France. These extreme temperatures can have an impact on our health. If the severe cold plan has been triggered in several regions in order to shelter people on the street, low temperatures “constitute a danger for everyone’s health”, calls police headquarters.
Our body is in greater demand
Our body has a thermoregulation system which maintains it at 37°C, “the optimal temperature for its proper functioning”, recalls infectious disease specialist Benjamin Davido. Faced with the cold, the body becomes more active to maintain its level. “The vessels of the skin contract and decrease in size, in order to redistribute the blood in depth towards the vital organs”, explains health insurance. A phenomenon that “is accompanied by an increase in blood pressure, heart rate and activity. »
These reactions of our body to the cold can have a harmful impact on certain diseases. Cardiovascular risks are thus increased due to “involuntary contraction of blood vessels”.
VIDEO. What is the polar vortex, causing the cold wave in France?
Weight loss, sleep…
Since the body is more mobilized in cold weather, the idea is widespread that we burn more fat at this time. This is indeed the case. But the nutritionists interviewed point out that this is a minimal loss for the sedentary people that we are, who rarely spend hours in the freezing cold. “Even if it’s very cold, that won’t compensate for a big raclette,” says Florence Foucault, nutritionist.
Another popular belief is that we sleep better when it is cold, because the body needs to lower its internal temperature when sleeping. “What is recommended for adults is a temperature between 16 and 19°C” in the bedroom, explains Armelle Rancillac, researcher in neurobiology at Inserm and the Collège de France. Higher or lower, sleep becomes less good, because our brain wakes us up to regain control and regulate body temperature.
A drop in immunity
Studies also show that some of our immune defense mechanisms are affected by the cold, which would allow viruses to pass more easily. In this sense, “below certain temperatures, there seems to be a greater risk of getting sick,” notes Benjamin Davido. However, the immune system is not the only element at play, he emphasizes: viruses circulate more when it is cold and rooms are less ventilated, which exposes us more easily to germs.
In the most extreme cases, exposure to low temperatures can cause hypothermia (body temperature falling below 35°C). Exposed to extreme cold for too long, the body is no longer able to maintain sufficient heat to function. The heart slows down and can even stop if the person is not taken care of. Regularly, during periods of extreme cold, homeless people are found dead.
“Rough, peeling skin”
The cold also acts “on the skin, by attacking the protective hydrolipidic film” which causes drying and “rough, peeling skin”, explains Catherine Oliveres-Ghouti, dermatologist, member of the national union of dermatologists – venereologists. This is particularly true on the face, where “the skin is thinner”, declares the specialist, who advises hydrating it well to avoid drying out.
In cold, humid weather, frostbite can also appear, “from 5°C,” she adds. To avoid it, you must “avoid shoes that are too thin or too tight”. And in the most extreme cases, frostbite, or damage caused by freezing, can occur. It is then necessary to consult.
The specialists interviewed emphasize that to combat the cold, the important thing is to dress warmly, particularly the extremities, in order to keep your body at the right temperature. It is also recommended to cover your nose and mouth to breathe less cold air.