Hi everyone!

This text is a translation of this one.

I apologize in advance for the eventual translation mistakes.

Often in summer (as now in Western Europe), we face heat waves. In this text, I would share with you some tips to better live them and to manage the few medical problems that it can pose.

At home

The first major principle is to properly use the windows and shutters. At night, everything is opened to circulate the air and let the interior cool down (or at least, stay at the temperature from the outside). The day, the windows are closed to prevent warm air from entering, and the shutters to prevent the sun's rays from heating up the interior. To avoid turn on the lamps, only the shutters that are directly exposed to the sun can be closed in order to have light inputs.

If there is wind, it can also be used to cool down the interior air by wetting large towels that will be laid out in front of open windows. When the wind passes through, the water will evaporate and thus "store" the heat of the air, reproducing then the principle of perspiration. That is why you are as cold when you sweat and suddenly there is a gust of wind.

It is also on this principle that the "fridge of the desert" rests, a trick that comes from Africa and allows us to keep food fresh. This requires two terracotta pots laid one inside the other. We put what we want to keep in the smallest, and we put water in the largest, then we cover everything with a towel. The water will evaporate and cool the pot contents inside.

Always following this principle, you can cool a bottle of water with almost nothing by wrapping it in a wet towel. It is attached to a tree branch with a rope and we make it swing. This pendulum movement will create an artificial wind that will cool the water in the bottle.

On oneself

First of all, and although it may seem counter-intuitive, it is advisable to wear light clothing rather than being shirtless. As a matter of fact, a thin garment will absorb perspiration, which can then act as a heat transfer interface between your skin and the outside air, because water is a much better heat conductor than air. So, perspiration acts like the thermal paste that is disposed between a processor and a ventirad. To maximize this effect, we can use a cotton garment, cause this tissue has the ability to take time to dry well and to evacuate heat. That is why it is particularly not advisable in hiking, because it tends to cause or aggravate hypothermia (1). In summer, you can wear a shirt or a tee-shirt in order to use this effect, useful in summer and very dangerous in winter.

Obviously, avoid going out or doing physical activities, but if you are forced to do so, book them to the cooler hours of the day, very early in the morning (sunrise or before) or late evening (around sunset), because if the intensity of the solar rays decreases considerably in the late afternoon, the temperature continues to rise until sunset. We will therefore go out as soon or as late as possible.

You can also take fresh showers, but avoid using too much cold water to avoid any risk of thermal shock. This is especially true for the elderly and children. For example, the French recommendations recommend not to deviate by more than two degrees from the temperature of the body (2).

Finally and of course, consider drinking plenty of water to compensate for the losses due to sweating. Be careful, however, if you are disgusted by the water, do not force yourself because it can be a hyponatremia, that is to say a deficiency of sodium. In this case, eat a piece and wait a moment. A tomato or a piece of melon are ideal because they are tasty, they are easily found in summer, they bring nutrients and are refreshing. You can of course eat all you want, but avoid fat-rich dishes because their digestion requires a lot of water and energy.

Hyperthermia and dehydration

Let's talk first about hyperthermia.

Let's talk first about hyperthermia. It is defined as (thanks Wikipedia) : « Hyperthermia is elevated body temperature due to failed thermoregulation that occurs when a body produces or absorbs more heat than it dissipates. ». Clearly (in our case): it is when one is too hot because the ambient air is too hot (opposite the fever where it is our own body which heats too much).

It is characterized by dizziness, nausea, severe sweating, headaches and fatigue. If these symptoms are severe or they occur in a child, I can not advise you too much to seek medical advice from your doctor, or even to emergency services (911 in North America, 112 in Europe).

The treatment consists mainly in leaving the person affected at rest, in the cool and in the shade, carefully monitoring his level of hydration.

Regarding dehydration, it is first noticed by feeling thirsty (so far, it seems logical), then followed by fatigue, headaches and nausea. The urine becomes little abundant and dark yellow or even brown. The skin is dry and wrinkled.

If you are facing a dehydration situation, regularly give small amounts of slightly salty water to the victim and seek medical advice.

Finally, as regards the rays of the sun, there is not much else to do but to avoid exposing itself to it. Shade is by far the best prevention of sunburn. Also think about taking out your sunglasses if you have to go out, which will reduce your eyestrain as well as protect your eyes.

(1): Source : Why Cotton Kills, A Technical Explanation.
(2): Source (sorry, in french). This document should be treated with caution, however, as it deals more with fever than with hyperthermia.

Summary

Thanks for reading me! If you have any questions or remarks, do not hesitate to let me know in the comments of this text. Take care of yourself, and see you next time! ;)

Licence

This text is published under the licence « Creative Commons By-SA 4.0 rezemika ». Its header picture comes from Pixabay and is under the licence « Creative Commons Zero dimitrisvetsikas1969 ».

Sources (sorry, many are in french)

• CEETS : Survivre à la canicule ;
• Tout sur l'hyperthermie ;
• Wikipédia EN : Hyperthermia ;
• Wikipédia EN : Dehydration ;
• Manise, D. (2016). Manuel de vie en milieu naturel. Paris: Editions Amphora. Pages 25 et 120.