This week, temperatures increased in a spectacular way throughout the territory, with very concrete consequences on organisms – especially among the most fragile individuals, such as small children or our elders. In this context, one can legitimately ask ourselves: can we really accustom our body to this warmth, that is to say acclimatizing, or are we condemned to suffer from it?
Acclimatization, the key to our heat resistance
This term designates a set of reversible physiological responses which allow an individual to better support a change in his environment. And fortunately, the natural selection process has equipped mammals – including humans – with a wide range of mechanisms that allow them to better resist temperature increases.
When the latter increases, the body detects heat thanks to many organic sensors called thermoreceptors. The latter activate different neurological routes as well as a response from the hypothalamus, a small structure of the brain located at the level of the brainstem which plays a central role in the coordination of acclimatization.
This process generally starts after 3 to 5 days of heat exposure, and reaches a peak one to two weeks later – a delay which can vary depending on many factors. Great athletes, for example, tend to acclimatize much faster, especially when they are specifically exercised in restrictive conditions.
How does it work?
But if the chronology can vary, the basics of the process remain the same in all individuals. The first consequence, and the most obvious, is Increase in sweat – The production of a mixture of water and salt by the sweat glands.
This perspiration indirectly contributes to the cooling of the body. During sound evaporationshe participates in dispel In order to maintain a normal body temperature. When perspiration becomes more abundant and occurs earlier than usual, it is a sign that the organism began to acclimatize.
And it’s not just the amount of sweat produced. Indeed, the salts contained in this liquid are a very important resource for many vital physiological functions. It is therefore important to save them. It is for this reason that acclimatization also produces a change in the chemical composition of sweatwhich becomes more and more diluted and less loaded with salt.
However, the human body contains only a limited amount of liquid. To support this increase in perspiration and avoid dehydration, they are the kidneys who then start to work. Under the influence of hormones like aldosterone and vasopressin, these organs start to remember more water and salt, reducing the production of urine and the loss of fluids.
In practice, this allows the body to increase its plasma production – the liquid part of the blood. We therefore have more fluid in circulation in the body at a given time. And it is very important in this context, because blood is the main vehicle thanks to which our body can carry the heat from one place to another. This allows the body to better transfer heat to the skin, where thermal energy can be dissipated to the environment.
A very effective process … within certain limits
You will understand: our body is remarkably well suited to temperature increases, and it is able to get used to it spontaneously … But it is only true to a certain point. There are hard physiological limits, Like the quantity of fluid that the circulatory system may contain, which make the body will never resist permanently in extreme heat.
In addition, as mentioned above, acclimatization is a Temporary and reversible process. After one or two weeks without continuous heat exposure, most of its effects disappear. Only a tiny part of this tolerance persists over a long duration, and the body must therefore relaunch this whole process to recover it with each episode of strong heat.
In addition, even if acclimatization helps maintain normal physiological activity, it does not prevent all physical damagelike burns that are commonly called ” sunburn ». You might think that sweat helps to protect itself from it, but it’s all the opposite. Not only does it not block ultraviolet radiation, but it can even increase the sensitivity of the skin by causing irritation.
Finally, the acclimatization potential varies considerably from person to person. Certain genetic predispositions, but especially age and state of health largely condition the effectiveness of acclimatization. The sweatshot glands of infants, for example, are not yet completely mature, and they therefore tend to sweat less. The elderly, for their part, often see the performance of their circulatory system decrease. Heat transport inside the body is therefore less effective. In both cases, these individuals have more difficulty regulating their internal temperature.
Help your body, and your body will help you
All the stakes, during periods of heat wave like the one we are currently going through, is to make sure not to push the organism too far and to provide it with everything it needs to acclimatize properly.
First, it is important to limit exposure to these strong heat by actively looking for fresh and shaded areas. And even if it is absolutely obvious, we will never repeat enough that The top priority is to hydrate. Each milliliter of fluid is a munition that the body desperately needs to conduct its war against heat, and it is therefore necessary to provide it abundantly and regularly.
Health professionals recommend that adults drink at least Two to three liters of water (or not No caffeinated or alcoholic beverageswhich accelerate dehydration) per day during periods of high heat. Obviously, this figure increases considerably in the event of intense physical activity; In this case, it is crucial to hydrate very often, without waiting for the first signs of dehydration.
This point is also very important for young children and seniors. The latter, in particular, often tend to lose part of the feeling of thirst; Dehydration with potentially very serious consequences can therefore occur without preventing. So be sure to get news from your loved ones, and make sure they drink enough and regularly!
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