RISKS DUE TO WEATHER CONDITIONS
A. ATMOSPHERIC TEMPERATURE
1. COLD
Brrr… this time for sure, winter is on its way.
But the need to move does not decrease with the temperatures! How to motivate yourself to play sports even when it's cold, and especially what activities are still feasible whatever the weather?
AT) MOVING WHEN IT'S COLD IS MORE DIFFICULT ...
Sports in winter? yes but…
There is the cold and the equipment that it requires, not to mention viruses, the ground which can be slippery or covered with snow thus hiding obstacles, the night which falls much earlier…
In short, to sport outside when it's winter is more difficult. Many fans of running or cycling therefore find it difficult to reach their quota of hours of sport per week when the good weather has worn off.
The gym, an easy solution
It's a budget, not the most glamorous of solutions, and apparently the gyms are one of the most polluted places (1). But they remain essential for some athletes, thanks to a long list of advantages:
They are easy to find (in all the big cities at least), open every day and according to long hours, offer showers to stay presentable, in short, they adapt to your requirements.
The activities are very varied and you can take the opportunity to introduce yourself to new sports that you can then practice anywhere: Zumba and others are often offered.
B) YOU CAN ALSO PLAY SPORTS OUTSIDE WHEN IT'S COLD
It is not because the beautiful season is over that you have to give up your breath of fresh air… Nordic walking , for example, is practiced in all seasons, except bad weather.
Some tips for going outside even in winter:
Cover up well, but by multiplying the layers to be able to discover yourself when the effort warms you up. All the same, stay well covered! Do not forget the gloves (sometimes the cycling mitt ) and the cap
Consider putting on a UV protective cream if the sun is shining and you go out for a long time.
Muscles are cooler in winter than in summer, naturally. The warm-up must therefore be particularly careful. Objective to raise the T ° of the body so that the blood vessels dilate and that the circulation is optimal during the effort. If possible, practice this warm-up indoors (stairwell)
C) WHEN THE WEATHER SHOULD DETER YOU FROM PRACTICING IN COLD WEATHER
Speed sports such as cycling should be avoided in the middle of winter (wind chill) : prefer mountain biking in the forest.
Running, cycling, football to be avoided when there is ice and in case of snow because we do not always see the obstacles or the traps that it hides ... even on a 'RAVEL' a branch can be hidden
D) WINTER SPORTS IN ALTITUDE
The higher you go, the colder it gets. In theory, the average temperature drops by 0.6 ° per 100 meters of altitude. So when you stay in Chamonix in winter, when it's 5 °, you will have -24 ° at the top of Mont Blanc, or you will have between -5 and -15 ° at the top of the highest ski lift . We must therefore dress accordingly.
E) THE EFFECTS OF WIND VELOCITY = THE WIND CHILL INCREASES THE FEELING OF COLD
Wind chill is a sensation that is felt directly by the body of a warm-blooded living being. The movement of air , by itself, does not lower the temperature. However, a man or an animal forms a layer of air on the surface of their skin due to their internal metabolism. Air is an excellent thermal insulator and this layer trapped in clothing or fur keeps the skin at a constant temperature 2 .
Normally, only convection removes this heated air. However, when exposed to the wind, the body loses this protective layer and constantly brings room temperature air into contact with the skin as the body tries to replace the warm layer. This mechanism occurs when the air temperature is lower than the thermal equilibrium temperature. In addition, when the temperature is high enough, water , especially perspiration , evaporates and creates a zone of moist air around the person. The air movement also drives out this humidified air and brings in drier air, thus promoting evaporation and therefore cooling.
The feeling of cooling is variable from one individual to another and the wind chill index is a quantification of the rate of heat loss. It is not applicable to an inanimate object, such as a car, because this one will quickly lose its heat to reach that of the air and the wind chill will no longer exist afterwards.
The lower the temperature, the greater the impact of the wind on the temperature perceived by the human body. Thus, according to the concept of wind chill factor, it is possible to estimate that at −20 ° C, a wind of 50 km / h lowers the temperature perceived by the body by 15 ° C, i.e. equivalent to a temperature of −35 ° C in calm weather (no wind). Therefore, the Nordic countries being colder, they are more sensitive to this subject than temperate or hot countries. In Canada , for example, wind chill is indicated in weather reports. Wind chill values are useful indications, for example, for cyclists and motorcyclists to visualize the cooling to which their body is exposed as a function of their speed of movement.
Hypothermia can therefore result from prolonged exposure of the body to a cold environment, such as the outside air in winter or a prolonged stay in cold water ( shipwreck ) or in an avalanche , or from deregulation of the organization.
F) INDIRECT CAUSES OF HYPOTHERMIA
(1) VICTIMS OF ACCIDENT OR ILLNESS
Hypothermia is a common complication for someone who has had an accident or who is unwell ; that's why accident victims should always be covered with a survival blanket (sheet of metallic paper)
(2) THE INTOXICATION TO CERTAIN SUBSTANCES ( ALCOHOL , BARBITURATES ),
There are cases of hypothermia among the homeless throughout the year in France, including for outdoor temperatures above 10 ° C 2 . These cases are attributed to a chronic disorder, primarily chronic alcoholism .
G) HOW TO PROTECT YOURSELF FROM THE COLD?
To prevent hypothermia, it is vital to provide adequate coverage of vital organs (such as the heart and brain ) during low temperatures. Indeed, the body , to fight against hypothermia, will monopolize and flow blood into the heart and brain . It is for this reason that it is first the ends of the fingers and feet that are victims of frostbite , because the blood no longer irrigates these parts of the body, to keep the vital organs at the right temperature. Therefore, if the vital organs are not well covered, by a good jacket for the trunk and a cap on the head , for example, the heat loss is therefore likely to be very important, because this is where it is. the greatest amount of blood. It is therefore of little use to have gloves on your hands if the vital organs are not kept warm.
In the marine environment, during shipwrecks and more generally abandonment, it is recommended to put on an immersion suit to slow the establishment of hypothermia. In fact, the body cools down 25 times faster in water than in air, so it is essential to isolate yourself from it. It will be noted that without this protection and in water at this temperature, death occurs in about fifteen minutes .
In your pocket, take a balm of the Pyrenees balm. Have heaters either disposable or reusable An adapted diet promotes your resistance It is also necessary to hydrate regularly with hot or cold drinks by eliminating alcohol.
Alcoholic drinks do not protect against the cold and do not allow you to warm up, on the contrary. The body's first defense is the energy-consuming thrill. Pack energy bars.
In the event of forced immobilization, shelter must be found which, even precarious, will protect from the effects of the wind (which considerably aggravates the cold). If possible, you should not keep wet clothes on you. Humidity multiplies the harmful effects of cold.
When you go to the mountains, even in summer, it is essential to check the weather forecast beforehand and to take orientation tools with you: map, compass or GPS. It is essential to respect the timetables (to avoid getting lost at nightfall). Bringing a cell phone can also help.
Special case ... cold in the water
In water , cooling is 20 to 30 times faster than in dry air. When you're stuck in cold water, it's paradoxically better not to move. Exercise produces calories which escape the surface of the body without warming it. Plus, swimming in cold water is exhausting. If possible, keep the neck out of the water (where the temperature control receptors are located).
H) SIGNS OF HYPOTHERMIA
It all depends on the body temperature:
at 34 ° C, it is a moderate hypothermia : the subject is tired, he has difficulty speaking, his hands and feet are numb, he shivers a lot and his skin is cold. It is at this stage that measures can be taken on the spot so that the hypothermia does not worsen. In the following stages, attempts at warming can be dangerous and precipitate heart attacks;
at 32 ° C, the skin is cadaverous and, a very important sign, the subject no longer shivers. He can make incoherent, sometimes violent, remarks. He may even pretend to be too hot;
at 30 ° C, he is stupefied, his muscles are stiff, his skin is purplish;
at 28 ° C, the subject is in a coma but still reacts, his jaws are clenched, his breathing irregular and his pulse very slow;
at 25 ° C, he no longer reacts, his breathing has stopped, we no longer feel his pulse and his pupils are dilated: he is in a state of apparent death. It is not uncommon that, even at this stage, the subject recovers without sequelae if a specialized team has been able to quickly set up resuscitation. Indeed, even deprived of oxygen, the brain is preserved longer if the body temperature is very low. On the other hand, at 37 ° C, the brain can stand the absence of oxygen for only three minutes.
Before the stay in the mountains
• Adapt to the cold if possible by provoking some resistance. • Prepare to be in good physical condition . • Buy suitable clothing . • Be careful above all and vigilant when consulting the weather forecast.
Altitude and cold go hand in hand.
The bodies of those who were not born at altitude or who do not live there regularly are not ready to easily endure the aggression caused by the lack of oxygen, the decrease in barometric pressures, and the cold. Caution is required, and the advice of mountain professionals remains the best way to have a good mountain vacation.
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