With the unusual heat waves that recently hit India and Pakistan and the heat wave that hit France in May, we are interested in the tolerance threshold for humans. Die of heat, simple expression or real possibility?
The thermometer no longer waits for summer to climb. In France, this month of May 2022 is particularly hot. In particular, several temperature records were reached and the mercury exceeded 37 degrees in places.
In Asia, the heat tolerance threshold for humans was even crossed a few days ago. And the consequences are dramatic: in the Indian state of Maharashtra, 25 people have died since March because of the heat. In addition, mortality linked to heat waves in India, already the victim of deadly heat waves in 2015 and 2019, has increased by more than 60% since 1980, according to the Indian Minister of Earth Sciences, as reported by our colleagues from the Huffington Post. In question: global warming and the phenomenon of the « heat dome ».
What is the heat dome phenomenon?
This is a phenomenon well known to meteorologists, already responsible for significant heat waves, particularly in Canada last July. The term is used when an anticyclone stays stuck in an area for a long time. « This is the case in France, with an anticyclone which came to position itself in April and which blocks the masses of hot air on the territory », details Alix Roumagnac, meteorologist from Hérault.
This is an immediate consequence of global warming. And it is the same phenomenon that is at issue in India and Pakistan
In addition, under the action of greenhouse gases, the sun’s rays are more aggressive and temperatures are rising more rapidly.
The homeothermic organism of the human being
However, the human body is indeed not able to cross certain limits. Homeothermic like most mammals, man regulates his own body temperature thanks to the hypothalamus which keeps it below 35 degrees, recalls caminteresse.com.
If the body reaches 35°C, it may overheat. This value takes into account the air humidity to measure our heat resistance, details The Huffington Post. The human body does not tolerate heat and humidity very well..
A study of theAmerican Physiological Society published in January 2022 confirms this. The latter measured the ability of healthy young adults to perform simple tasks in six different extreme weather conditions. The experiment of a few hours revealed thatno participant reached the limit of 35° Tw, the temperature threshold.
In some people, when this threshold is reached, especially the most fragile such as the elderly, the heartbeat accelerates, the skin becomes red and dry, nausea and vomiting may occur, sometimes convulsing, losing consciousness. .or even fall into a coma. Without immediate care and cooling, death ensues.
A study by the University of Hawaii and published in the journal Circulation: Cardiovascular Quality and Outcomes in 2017 thus listed 27 physiological pathways by which humans can die of heat. Death can occur as a result of heart failure, brain damage or cell degradation.
And if you go to a sauna? Thanks to the evaporation of sweat, perspiration ensures the constancy of the internal temperature of the body. This mechanism is easily set up when the climate is dry. For example, you can go to a sauna at 100°C for 15 minutes without risk, specifies RTL.