This weekend, many European countries will adjust their clocks back by one hour, marking the conclusion of daylight saving time (DST). While this twice-yearly time shift is a long-standing tradition in Europe and other regions, experts caution that it may negatively impact health.
On Sunday, clocks will roll back an hour, signaling the end of DST, which involves moving clocks forward in spring and back in fall. Though widely practiced in Europe, the United States, parts of Canada, Australia, and Latin America, health professionals are raising alarms about the potential adverse effects on well-being.
Recently, a group of sleep researchers from the British Sleep Society published a position statement advocating for the UK government to abolish these seasonal time changes. Their report, featured in the Journal of Sleep Research, recommends adopting standard time year-round, as it better aligns with natural light-dark cycles.
“By establishing permanent standard time, our clocks would more closely match solar time,” explained Malcolm von Schantz, a professor of chronobiology at Northumbria University. “While this would lead to earlier sunsets in summer, the health benefits from improved sleep and better circadian alignment, thanks to increased morning sunlight from autumn to spring, would be significant.”
The researchers emphasized the importance of a consistent sleep routine and morning light exposure for overall health, noting that disruptions can lead to various negative health outcomes. Dr. Megan Crawford, a senior lecturer in psychology at the University of Strathclyde and lead author of the statement, pointed out that lack of morning light can hinder the regulation of our body clocks, resulting in poorer sleep quality.
“If morning light exposure is lacking, it becomes challenging to maintain a proper sleep schedule, leading to sleep deprivation and associated health risks, both mental and physical,” Crawford added.
The Impact of Daylight Saving Time on Health
One of the main concerns raised by experts is the effect of time changes on the human circadian rhythm, our body’s internal clock that regulates various functions, including sleep, hormone production, metabolism, and mood. Disruptions from losing or gaining an hour of sleep can interfere with these crucial processes.
Crawford noted that while the time change may not have significant effects in summer—when sunlight is plentiful—it poses challenges during spring and autumn. “In these seasons, we may find ourselves waking up in the dark, which is problematic because morning light is essential for regulating our body clocks and ensuring quality sleep,” she stated.
Research supports the notion that proper light exposure helps maintain the circadian cycle. Morning sunlight promotes wakefulness, while exposure to artificial light at night—common during time shifts—can complicate the ability to fall asleep and wake up at appropriate times.
Numerous studies have linked the time change to various health risks. For instance, a meta-analysis involving over 100,000 participants found a significantly increased risk of heart attacks in the weeks following the transitions. Another Finnish study indicated a rise in stroke hospitalizations in the immediate days after the time change. Additionally, research has shown correlations between DST transitions and increases in mental health issues, including heightened suicide rates among vulnerable populations.
Crawford believes that resistance to abolishing time changes stems from a “lack of understanding” and reassured that the benefits of longer evening daylight in summer would persist, regardless of whether DST is implemented. “Many people think that DST creates more daylight, but that’s not the case. The sun’s schedule doesn’t change with our clocks.”
Europe’s Position on Daylight Saving Time
In 2018, the European Commission proposed an end to the biannual clock shifts within the EU. This proposal included an online consultation to gauge public opinion, which showed significant support for eliminating the practice. In some countries, like Poland and Finland, support reached as high as 95%, while it was around 44% in Greece. On average, about 84% of EU residents favored the change.
Despite the European Parliament voting in favor of the proposal, the European Council has yet to reach an agreement, allowing the practice of daylight saving time to continue.
