Time change: Why it's wrong to say we're going to sleep an extra hour

France switches to winter time during the night of Saturday October 24 to Sunday October 25. At three o'clock in the morning, clocks will turn back one hour to two o'clock. This annual adjustment has become a subject of increasing public criticism despite its long history. The practice was reintroduced in France in 1975, with some sources citing 1976, under President Valery Giscard d'Estaing. The primary motivation at the time was to reduce energy consumption during the global oil shock by aligning working hours more closely with daylight availability. While many residents expect to gain a full extra hour of sleep during this transition, new data suggests the reality is far less generous. A study conducted by French connected watch manufacturer Withings analyzed approximately 244,321 nights recorded by its devices during clock changes in France between 2023 and 2025. The findings indicate that the average person sleeps only 14 minutes longer on the night of the switch, rather than the anticipated sixty minutes. This discrepancy arises because the human body does not automatically utilize the additional time for rest. Dr. Pierre Escourrou, a cardiologist and sleep specialist, explained that internal biological clocks are regulated by light exposure and daily habits. These rhythms do not shift immediately just because wall clocks change. He noted that as evenings grow darker, maintaining regular routines and seeking morning sunlight becomes crucial for health. The impact varies significantly across Europe and within France itself. According to the Withings analysis, citizens in Denmark and Norway gain only ten extra minutes of sleep, while Finns get eleven. Germans, British, and Swedes gain twelve minutes. Italians record the highest increase among European nations, adding fifteen minutes to their nightly rest. Within France, regional differences persist. Residents of Marseille benefit the most, sleeping nineteen minutes longer. Those in Toulouse gain seventeen minutes, followed by Lille with fifteen and Paris with thirteen. Lyon records the lowest gain, with an additional eleven minutes of sleep. Despite these modest increases, fifty-nine percent of French participants in the study did sleep longer than usual on the transition night. The timing of the switch follows specific European Union regulations designed to harmonize practices across member states. Although the spring forward date was standardized in 1981, the autumn back date remained variable until later directives. In 1996, the European Community proposed following the British model, which changed clocks on the last Sunday of October. A final directive entered into force in 2001, making this rule definitive. The choice of Sunday minimizes disruption to economic activity and traffic, which are at their lowest levels compared to weekdays. Selecting the last Sunday of October provides simplicity, as no annual decision is required and the date is easy to anticipate. Previously, countries like the United Kingdom and Ireland switched at the end of October, while much of continental Europe moved clocks earlier in September. This misalignment complicated cross-border trade, communications, and transport schedules for nearly a month each year. Certain French overseas territories, including Guadeloupe, Martinique, French Guiana, and Reunion, are exempt from these metropolitan rules. For those in mainland France, the immediate consequence beyond sleep patterns is the early onset of darkness. Sunset will occur around five thirty p.m., prompting households to adjust indoor clocks and prepare for shorter days. The debate over the utility of daylight saving time continues, with critics questioning whether the energy savings originally promised justify the physiological confusion caused by shifting the calendar twice a year.