France switches to winter time

In the night of October 24 to 25, 2026, France will switch to winter time, setting clocks back one hour to 2 am from 3 am. This change allows people to sleep one hour longer but may have negative effects on sleep quality, according to Armelle Rancillac, a neuroscientist and sleep specialist.

Potential negative effects on sleep

Rancillac notes that while the extra hour of sleep may be beneficial for a sleep-deprived population, it shifts the sleep window and may impact the quality of sleep. This shift could affect numerous sleep-related functions, including learning, immune defenses, mood regulation, and metabolism.

How the body's clock is affected

Rancillac explains that the body's biological clock, managed by the hypothalamus, is influenced by daylight and the secretion of hormones like cortisol and melatonin. However, the hypothalamus may take time to adapt to the time change, potentially causing sleep disruptions.

Who is most affected by the change

According to Rancillac, half of the population is generally affected by the time change, with children, women, the elderly, and those with pre-existing sleep disorders or comorbidities being the most affected.

How to prepare for the time change

To prepare for the time change, Rancillac suggests gradually shifting bedtime and dinner time a few days in advance. For example, adjusting bedtime and wake-up time by a quarter of an hour over four days or twenty minutes over three days may help ease the transition.

Ongoing debate about time changes

The debate over whether to continue switching between winter and summer time remains unresolved in Europe. While the majority of the French prefer to keep summer time, Rancillac suggests that winter time may be better for the body due to the importance of morning light. However, no definitive decision has been made on whether to stop the biannual time change.