The Sahara is the warmest on Earth, with temperatures above 50 ° C not uncommon. A challenge to the physiology of the human body! Thermoregulation or regulation of body temperature can drain all energies and survival is impossible for more than a day or two without water.
The Bedouins know it better than anyone else: To resist the sun and the heat, this nomadic population roaming the deserts from Morocco to Arabia has developed real strategies … some of which contradict received ideas. Here they are in seven points.
1. A ventilated habitat rather than sealed
In hot deserts, unlike in cold environments, the goal is not so much to close off, unless to find refuge in a dwelling made of insulating materials, such as stone, as to find an airy shelter. The nomads’ tents offer a temperate asylum, on condition that they are opened to favor the installation of an air stream that evacuates the heat. In fact, the substance affected by the sun’s rays stores heat and heats the air on contact. This rises and creates a flow of air by convection, which sucks less warm outdoor air under the tent. And the darker the canvas, the warmer the surface and the greater the convection motions. And the efficient canvas fan!
2. Faced with the heat, drink a lot … and hot
To compensate for water loss through sweat, it is necessary to rehydrate continuously: in the desert it may be necessary to drink up to 10 liters of water a day. And paradoxically, cold drinks are not the right parade. As proof: the Bedouins have made burning mint tea a real ritual and consume it several times a day. And if you get hot from drinking hot, it is a blessing in disguise because the high temperature of the liquid increases the internal temperature of the body and thus stimulates sweating. Sweat beads and evaporate the dissipating body heat. In the end, in the desert, a hot drink turns out to be refreshing!
3. Beware of thermal shock at night
In summer in the desert, the thermal amplitude varies from 45 ° C during the day to 15 ° C at night. Fire is welcome
at the dawn of darkness, both for cooking and for lighting or heating. The camp is often established according to
different criteria: sheltered from the wind behind rocks, well oriented to delay the incidence of the first rays of the sun and have shade. Mats placed on the blankets allow you to sleep on the floor in the tents, with or without a sheep wool blanket.
4. Eat light and salty
In scorching heat, it is better to avoid dishes that are too heavy to digest. Ambient heat promotes irrigation of peripheral areas of the body to the detriment of internal organs such as the digestive tract. Digestion is therefore more difficult. These are not fasts. The Bedouins prefer foods rich in fiber and water (vegetables, milk, pita, soup, poultry, etc.) to which they add a little salt. In fact, sweat causes you to lose, in addition to water, many mineral salts, especially sodium. It is therefore important to compensate for this loss by eating salt (sodium chloride), under punishment for developing serious disorders: muscle contractures, malaise, seizures, difficulty breathing … Not to mention that it is now proven, contrary to what you may think that eating salt makes you less thirsty!
5. Do not believe the sun
When the temperature approaches 50 ° C at noon, the slightest physical effort, even walking, becomes an ordeal. Some of the energy supplied to move is converted into heat. However, when the outdoor temperature is very high, it becomes difficult to evacuate this additional heat. In fact, the mechanisms based on the temperature difference between two media (convection) are ineffective. That’s why the first trips in the desert are made early in the morning, before 8.30am, to take advantage of the night’s persistent coolness.
6. Dress in dark colors and plan for multiple layers
In hot weather it is tempting to cover. A false good idea because the skin is then exposed to sunburn. The Bedouins cover themselves from head to toe to protect themselves. They wear at least two layers of loose clothing (a cotton shirt and trousers – the sarouelen – worn next to the skin and covered with thoab, similar to a cloak), which, as with the tent, promotes convection between the layers. The air heated by the outer layer rises inside and escapes through the neckline. This movement draws the cooler ambient air in through the bottom of the thoab. The air flow thus created allows the sweat – which absorbs the body’s heat – to evaporate and thus cool it.
7. Protect your skin from UV rays
In the desert, not all men have black skin. Some, like the Bedouins, are white people with dull, tanned skin. Their skin is partially “protected” by melanin. The pigment that gives the skin its color and contributes to its thickening. As this is darker than in white Europeans, it gives them natural protection from the sun. UV rays, although very intense in this desert environment, reach less to the deep layers of the epidermis. 50% or more for light skin tone, 15% for dark skin. If you do not have tanned or dull skin, it is essential to use sunscreen with a high index (50), just as it is to wear a cheich (scarf), which, pulled up over the nose, reduces the exposed surface. Glasses, on the other hand, protect against both sun and sandstorms!
An article originally published in 2017 in Science & Vie QR # 16 “Our Five Senses and Their Mysteries” – Browse This Issue – Buy This Issue