HOW THE BODY CONTROLS TEMPERATURE
(1) REMINDER
In order to function properly, our body temperature must remain around 30 ° C at all times. Body temperature is tightly controlled by a "thermostat" located in an area of the brain called the "hypothalamus". When the body temperature of the body rises above the "limit", the hypothalamus activates various mechanisms of heat loss: breathing quickens and becomes shallower; blood circulation to the skin increases; and sweating increases.
In humans, most of the extra heat is dissipated through the skin. The blood transports heat from the main body tissues to the skin. The heat is then transmitted from the skin to the environment in the following ways:
Conduction: heat passes from the skin to a cooler object
Convection: cooler air currents remove heat from the skin
Radiation: the skin emits small amounts of radiation energy
Evaporation: body heat is used to convert perspiration into water vapor
If the surrounding air is cold and dry, it is easy for the body to get rid of the heat. The hotter it is and the more humidity, the harder it is to get rid of the heat:
If the air is as warm or hotter than the skin, around 36 ° C, the body will absorb heat from its surroundings. The only cooling mechanism that still works is evaporation.
If a person is in direct sunlight, especially if they are wearing dark colored clothing, the body will absorb heat from the sun.
If the air is also very humid, evaporation no longer works properly. Therefore, we sweat profusely, but we don't lose much heat.
In other words, when we expose ourselves to high temperatures, high humidity, and direct sunlight, the body has to work harder to get rid of the excess heat.
Running in the heat does not melt fat !!!!
SLEEP first: a little reminder: hot weather does not mean heatwave; we speak of a heat wave of course when the temperatures are very high, but especially when the temperature does not drop below 20 ° at night; and if it is hot at night we do not recover from stress and emotional fatigue because we do less paradoxical sleep (= paradoxical sleep, that of dreams) Day after day fatigue sets in, often accompanied by emotional disorders , psychological tensions, headaches. And that's why in hot countries life stops at the beginning of the afternoon: it's nap time, to compensate for this lack of sleep, while the "people of the north" continue. at …. Getting agitated … Of course, sports activities should take place early in the morning, or really at the end of the day.
CLOTHING Make sure you wear fairly light clothes (put on a black swimsuit and a white swimsuit in full sun, come back after an hour: the white swimsuit is cool, the black is hot because it absorbs the sun's rays), loose (so that the air circulates and cools the skin by allowing the sweat to be absorbed by this air), light. There are suitable fabrics (this site does not advertise but major brands offer ranges of loose, light sportswear, with an air circulation system)
Wear a light cap, very light in color, not too tight on the forehead.
Drink regularly (200 to 400ml) of plain water during the hour before the start of training or the start of the match or race.
During the effort of course you have to drink, a little by a little bit, from the start, without waiting to be thirsty; if the effort lasts less than an hour, plain water is sufficient; beyond an hour, add a little sugar (syrup) and ESPECIALLY SALT to the drink: at a temperature of 30 °, add to the drink (unless it is a sport drink already mineralized) 3 pinches of salt for 500ml.
On a stage of the Tour de France, but also on the last French road championships (the temperature was 35 °, 250 kms, 6 hours of races, from 9:30 am to 3:30 pm… ..) a cyclist drinks up to 12 cans of 500ml, and even with this quantity of liquid it becomes dehydrated (you can never compensate for more than 80% of the water losses) You should drink about 2 sips every 12 minutes. Do not drink iced; but of course the drink in the cyclist's container, for example, heats up in the sun; stop to fill your cans: a café, a cemetery!
Rinse the face well with plain water (avoid syrup… for flies!), It washes the salt from the sweat that stings the eyes; and with speed (especially by bike) the air absorbs this water and brings a feeling of real freshness (it is the absorption of sweat or water which decreases the temperature of the skin by "extracting" the heat ) On refreshments (cycling, running) we can offer sponges soaked in water.
Wearing glasses (not too tight)
Skin protection (high index) but…. With sweat it is not easy, especially on the face. There are sun creams suitable for sports.
When the nature of the effort allows it (leisure training, excursion, walk, quiet bike): take breaks in the shade, cool off, rinse your face.
If the slightest dizziness appears, the slightest headache: beware, “heatstroke” is announced: stop the effort, get in the shade, drink, sprinkle.
A RULE: STOP THE ACTIVITY AT THE LEAST SYMPTOM.
The more humid the weather, the more we become dehydrated because the sweat cannot evaporate.
Also regularly spray the neck and forehead.
Wet the cap.
Take shaded routes: forest trails, or ride in the shade.
Reduce the intensity of the effort, avoid working in intervals.
Please note that asthmatic athletes are vulnerable: the hot air they breathe attacks the bronchi.
Of course, it is out of the question for a child to practice a physical or sporting activity not in full heat (except swimming!): The younger the child, the more water his body consists of, the more fragile he is to dehydration. .
No sport or physical activity in the heat for the person over 65, or a person with a pathology .
WHEN WE LOSE 1% OF ITS WEIGHT IN WATER, WE LOSE 10% OF STRENGTH: for example a 70 kg athlete loses 10% of strength if he loses 700ml of water, 20% if he loses 1.4 liters.
I am a staunch defender of tap water, but in times of heat I recommend making up the cans with mineral water (but still)
On a cycling race, always take a bottle from the ravito, even if you don't need it, it will always be used by one of your teammates.
At altitude the risk of dehydration and heat stroke is even greater.
Be careful, sugar attracts insects, especially wasps. Glasses also protect against these insects.
Do not run barefoot (perspiration, friction, blisters)
Avoid wearing a camel - back that is too wide (the athlete will sweat on the back, and it reduces the exchange surface to evaporate his sweat)
Drink well in the hours following the end of the effort: very quickly the urine should be clear. As long as they remain dark you should drink.
It is necessary to bring salt in the drink during the effort, but especially not of Potassium because during the effort the blood is "concentrated" and the level of Potassium is high (because concentrated) On the other hand in the hours which follow an effort during when we have sweated a lot we can consume a teaspoon of Potassium Gluconate syrup; but this advice is intended for athletes who practice competition and medical advice seems compulsory to me.
Likewise, a regular supply of Magnesium is desirable during periods of heat.
ESPECIALLY : do not "go for it" immediately under a "good" cool shower, you risk thermal shock; the body must first be allowed to cool, in the shade, in a well-ventilated space.
CAUTION : after the effort, stay in a well ventilated area, in the shade, in a cool place; this for at least an hour; no question of "rushing" on a barbecue in full sun !!!
My technique to take advantage of the heat to achieve much better performance than my opponents :
Preventively cool the body
Cuffs and swimsuit 'frozen'
Warm-up in a covered and cool place (changing rooms)
Cover up well before the test and do not expose yourself to direct sunlight.
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