Our wise advice for resisting the cold (and avoiding some pitfalls)

Scream, it's cold. Nothing but very normal for the season, you will tell us. However, shivering, frozen noses and numb fingers are not the most pleasant part of winter, and some people are more at risk from negative temperatures. “Le Figaro Santé” has taken off its mittens to give you its best anti-cold advice and alert you to some pitfalls to avoid.

Our body constantly maintains its internal temperature around 37°C (with small variations depending on the organs, times of day and individuals). To resist the cold, it saves the heat it has, and strives to produce it. To save it and distribute it where it is most needed, a phenomenon of vasoconstriction appears: the blood vessels of non-vital parts (the skin, the fingers, etc.) see their diameter decrease. This has two advantages: on the one hand, less irrigated skin is more insulating, and limits thermal exchanges between our blood and the outside world. Blood will also flow to the vital organs to better protect them. It also becomes more viscous.

Second tactic of our body: producing energy. To do this, it will accelerate digestion to absorb the nutrients necessary to create heat, and draw from fats. Cellular metabolism accelerates to produce even more heat. The other way to produce heat is through movement, and shivering is the body's "second line of defense" against cold: superficial muscle fibers contract to increase heat production. The appearance of shivers therefore signals that the body is struggling to regulate internal temperature, and that it is time to go home! As for “goosebumps”, it creates an insulating layer of air between your skin and the cold outside; this very ancient mechanism is obviously more effective in an animal with a thick coat than in humans...

Flus, colds and other respiratory infections are due to viruses and bacteria and no, we do not “catch a cold” in the strict sense of the term (even if certain mechanisms mean that it is indirectly involved and that our resistance to them is less). On the other hand, in very young children and the elderly, thermal regulation mechanisms work less well. And this is all the more true if they move little or not at all. Remember that while you walk, your baby stays still in his stroller! Furthermore, children cannot tell when they are cold, especially if they are having fun. Also beware of chronically ill patients (cardiovascular or respiratory pathologies, hypothyroidism, neuropsychiatric illnesses): to fight against the cold, the body mobilizes precisely the mechanisms weakened by their pathology. Studies have thus shown greater cardiovascular mortality during episodes of extreme cold (9.1 additional deaths per 1,000 deaths, according to a study published in 2022 in the journal Circulation).

Frostbite and hypothermia threaten with prolonged exposure, and every winter, homeless people are found frozen to death. Frostbite is localized injury caused by freezing of the skin, most often on exposed extremities (hands, feet, face); It starts with redness and burning, then a feeling of numbness and skin discoloration or whitish spots. Frostbite should be treated immediately, to prevent it from developing into deeper frostbite. As for hypothermia, it starts when the internal body temperature drops below 35°C. The body can then no longer function properly. Chills, drowsiness, fatigue and general clumsiness are the warning signs. Below 32°C (moderate hypothermia) progressive unconsciousness and hallucinations appear. Below 28°C, it is serious hypothermia.

Another, more indirect danger: every year, people become victims of carbon monoxide poisoning due to poorly used or poorly maintained heating appliances and poorly ventilated rooms. Headaches, dizziness or feeling of weakness should alert you, as should digestive symptoms (nausea, vomiting, pain, etc.), especially if they affect several members of the household and disappear when they leave the home. If the intoxication persists, vision and behavioral disturbances, or even a coma, may appear. “For physiological reasons, [infants] can be the first or even the only ones poisoned,” specifies the Ministry of Health. The clinical presentation is often atypical (refusal to breastfeed, unexplained crying, torpor, convulsions).” Also be careful with pregnant women: the fetus can be seriously poisoned while its mother feels little or no effects. Whatever the outside temperatures, it is therefore essential to continue to ventilate your home.

Do you know what the best insulation is? The air, as long as it is dry and still! Whether you are in the city or at the top of a mountain, the secret is to “wrap” yourself in air to insulate yourself from the cold. There are two solutions for this: you can opt for an outfit designed for this (a down jacket, ski or hiking clothes, etc.), or layer several light pieces of clothing rather than just one very thick one (which, cherry on the top, cake, will make it easier to remove leaves when you enter a heated place). The clothes should also not be too close to the body (to be able to trap the layer of air), those in contact with the skin should be able to wick away perspiration, and the last layer should insulate you from the wind and rain.

Pay attention to the protruding parts. Your mother was not wrong when she told you to wear a hat, gloves and scarf... By protecting your nose and mouth, you will breathe less cold air, sparing your body from having to heat it up before it reaches your lungs; your mucous membranes will also be less weakened, and will thus form a better barrier against viruses and bacteria. The head, abundantly irrigated by the blood circulation, is a real source of heat loss if it is exposed. As for the fingers, they are the first sacrificed by the body which prefers to irrigate the vital organs, so do not count on it to protect them!

Resisting the cold requires effort from your body. The heart beats faster, blood pressure increases, as does the respiratory rate. If you are not in very good health or not used to physical exertion, now is not the time to start running.

In addition, extreme or prolonged cold reduces our performance and alertness. Muscle strength, dexterity (especially when wearing thick clothing and gloves), attention and reaction time can be impaired, so be careful if you engage in a risky activity, for example DIY. Also beware of the risk of slipping on frozen ground.

Normally, unless you are exposed to extreme and/or prolonged cold, your body does not need additional calories to cope. A balanced diet will be enough. However, you must take care to hydrate properly, especially as the cold tends to irritate the mucous membranes. Hot drinks may be nice, but they won't warm you any more than a simple glass of water. And whatever your pleasure in sipping a mulled wine or a grog, forget a preconceived idea: no, alcohol absolutely does not warm you up! It's actually quite the opposite: under the influence of alcohol, the blood vessels on the surface of the skin dilate and blood rushes there, giving us a false sensation of heat, to the detriment of our internal organs. !

The cold can have consequences on the stability of certain medications, and on their effect in our body. Medicines are tested for stability at high temperatures, but not always at low temperatures, and some products may see their quality reduced if exposed to extreme cold. In addition, they can alter our defense mechanisms. Neuroleptics, barbiturates and benzodiazepines disrupt the functioning of the hypothalamus, which controls central thermoregulation; some anti-hypertensives and vasodilators disrupt peripheral regulation; other products may see their absorption modified.