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Is it possible to die from heat ?

 Heatwave: Is it (really) possible to die from heat?

Heat wave: Is it (really) possible to die from heat?

Is it possible to die when the outside temperature is too high? An expert's answer.

Our body constantly regulates its temperature through various mechanisms controlled by the hypothalamus, a gland at the base of the brain.

"When the outside temperature exceeds 32°C, these mechanisms are activated to maintain an ideal internal temperature, i.e. close to 37°C," explains Dr Frédéric Le Guillou, a lung specialist and president of the French association of Respiratory Health.

More specifically, the body relies on four main mechanisms to deal with the heat:

  • Sweating: "Sweating reduces body heat by about 30%," says the expert,
  • Radiation: "Heat is naturally emitted by electromagnetic waves, which reduces body temperature by about 40%,
  • Treatment: "When a cold object is placed on the skin (e.g. a wet sweater), heat is transferred to it," says the lung specialist. However, conduction only allows 2-3 per cent of the body's heat to escape,
  • Conclusion: 'Heat is also partially transferred through air or water, for example when you are near a fan.

But when the outside temperature rises above 35°C, these temperature adaptation mechanisms become less effective and we have to work harder to keep our bodies at 37°C.

However, most of these temperature adaptation mechanisms lead to water loss: "In the lungs, for example, we see increased ventilation: the body tries to remove as much CO2-laden hot air as possible," explains Frédéric Le Guillou. This phenomenon is accompanied by an increase in water vapour emissions.

Heat: dehydration is the leading risk

The main danger in hot weather is dehydration: in the most extreme cases, the lack of water in the body can lead to death. "The people most at risk are babies, the elderly and people with chronic diseases (especially respiratory and cardiovascular diseases)," says the lung specialist.

In addition, to promote heat dissipation, the body will order vasodilation of the blood vessels just under the skin: "Unfortunately, this phenomenon occurs at the expense of other organs: we will thus observe vasodilation of the digestive tract, which can cause nausea and vomiting, exacerbating the dehydration," adds Dr Frederic Le Guillou.

In the most extreme cases (with temperatures above 40°C), thermolysis can be observed: "In other words, there is a direct heat attack on the temperature regulation centres: hypothalamic cells are destroyed, which can lead to death.

"As a preventive measure, it is necessary to drink plenty of fluids throughout the day without waiting to become thirsty (2-3 litres per day), limit physical activity and cool down the environment as much as possible, for example by using a fan or air conditioning," advises the expert.


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