Key Points

• According to Météo France, the red-alert heat wave that has been affecting the Pays de la Loire region since June 19 is expected to last at least until Thursday, June 25.
• A regional analysis of emergency care utilization shows a much larger increase in the composite health indicator iCanicule1 (which includes hyperthermia, dehydration, and hyponatremia) than what was observed in 2025. In 2025, there were three heat wave alerts in the Pays de la Loire region, none of which reached the red level.
• As for SOS Médecins, which operates only in Loire-Atlantique, its response to urgent heatwave-related conditions (hyperthermia, dehydration) is on the rise.
• The rise in health indicators is observable across the region as a whole, but particularly in Mayenne and Loire-Atlantique; the Vendée is also affected, followed by Maine-et-Loire and Sarthe, which are affected to a lesser extent.
• Heat poses a health risk to the entire population. The observed health impacts underscore the importance of implementing preventive measures to mitigate the effects of the heat.