This is exceptional for a month of June. 23 departments were placed Thursday, June 16 in orange vigilance in the heat. This alert system put in place after the 2003 heat wave aims to anticipate temperature rises that could pose a risk to health.
How are these alert thresholds defined? We go into orange vigilance when the risk of heat-related mortality is twice as high as the average. This happens when temperatures remain abnormally high for three days in a row day and night. Important clarification: these levels are established locally. This means that heatwave vigilance is triggered around the Mediterranean, when it is 35°C, 36°C during the day and 20°C to 22°C at night, explains Mathilde Pascal, epidemiologist at Public Health France while in Brittany, for example, the threshold is lower. It is enough to have nights at 18°C or 19°C and days at 32°C 33° for the departments to switch to heat wave alert.
This difference is explained because physiologically, the organisms are a little more adapted to the heat in the south and because, moreover, in the sunniest regions, the lifestyles, the dwellings, the layout of the cities are generally , better designed to cope with high temperatures.
Nighttime temperatures are also very important in triggering these heat wave alerts because normally at night, body temperature drops. The body releases heat to the outside, by dilating the blood vessels. But for this heat exchange to exist, the ambient temperature must obviously be low enough, which is not always the case when the buildings have accumulated too much heat during the day. In this case, sleep is much worse and bodies tire more quickly, especially in people over 65.
The cold shower is not a good idea to cool off because the blood vessels will constrict, so they will evacuate the heat less well, and the body temperature will rise more quickly afterwards. That’s why doctors recommend a lukewarm shower instead. Another tip: moisten the skin regularly to promote evaporation which provides an immediate feeling of freshness, which can be reinforced with a fan or a draft. Finally, doctors point out the importance of staying hydrated: drink 1.5 liters or two liters of water a day, to compensate for water loss linked to perspiration.