Key Points

A heat wave triggering the yellow and orange alert levels specified in the National Heat Wave Plan (PNC) affected 87% of the metropolitan population between June 17 and 25, 2017. The health impacts observed during this early-season episode underscore the importance of strengthening prevention measures in the workplace and among older adults.

This heat wave affected Brittany from June 17 to June 22 and was characterized by:

• An atypical weather pattern with a heatwave occurring earlier than those in 2015 and 2016, affecting all four departments; the department of Ille-et-Vilaine was affected by a heatwave for the first time since the implementation of the PNC.

• An observed number of deaths from all causes that remained in line with the expected number, both in the general population and among those aged 65 and older.

• There was an increase in heat-related emergency care: 128 emergency room visits and 33 SOS Médecins consultations for heat-related conditions, affecting all age groups, were recorded during the heat wave. The number of heat-related diagnoses is known to increase proportionally with temperature and to have a minor impact on overall healthcare provision (in the order of a few percent).