Key Points

In 2017, health monitoring conducted as part of the Heat Wave and Health Alert System (SACS) of the National Heat Wave Plan (PNC) revealed the following in the Pays de la Loire region:

• An early heat wave in mid-June (June 17–23) that affected nearly the entire mainland, prompting Météo-France to issue an orange heat wave alert for the departments of the Pays de la Loire region for at least one day. Nationally, 96% of the mainland population was affected by this episode.

• This heat wave was associated with a moderate increase in emergency room visits and SOS Médecins consultations for “heat-related” conditions, particularly hyperthermia and heatstroke.

• It was accompanied by a moderate excess in all-cause mortality of 6.6% compared to the expected number of deaths during this period.

This early heat wave led to several reports of clusters of heatstroke cases in schools. These findings confirm the significant link between daily maximum temperatures and hyperthermia, particularly when heat waves occur early in the season.

Although older adults remain the most vulnerable, hyperthermia primarily affects children and young adults. It is therefore important to remind people of preventive measures, such as proper hydration and limiting physical exertion, particularly for the most vulnerable (children and older adults) and those overexposed to heat (especially outdoor workers).