A groundbreaking study from Stanford Medicine researchers indicates that maintaining permanent standard time could offer substantial health benefits to the majority of the population, suggesting it is healthier than the current practice of shifting clocks twice a year for daylight saving time (DST).
The findings, published in the Proceedings of the National Academy of Sciences, explored the potential health impacts of three distinct time policies: permanent standard time, permanent daylight saving time, and the existing biannual clock changes. The research, led by graduate student Lara Weed and Professor Jamie Zeitzer, concluded that either permanent standard time or permanent daylight saving time would be healthier than the current system, with permanent standard time presenting the most significant advantages for overall well-being.
Disruptions to the body's natural circadian rhythms, which govern essential functions like sleep and metabolism, are increasingly linked to serious health issues such as stroke and obesity. The Stanford study estimates that a permanent adoption of standard time could potentially prevent approximately 300,000 strokes and reduce the prevalence of obesity by 0.78% annually across the United States. Permanent daylight saving time would achieve about two-thirds of these benefits.
Dr. Zeitzer emphasized the critical role of morning light exposure in maintaining a healthy circadian rhythm, noting that while evening light can delay it, morning light helps to accelerate and synchronize the body's internal clock to a 24-hour day. Medical and sleep organizations, including the American Academy of Sleep Medicine, have largely supported year-round standard time, citing its theoretical alignment with human biology.
Historically, daylight saving time was first implemented in the U.S. in 1918 during World War I as a measure to conserve energy. The Uniform Time Act of 1966 standardized the practice, with subsequent legislative changes extending DST to its current schedule. The findings from Stanford Medicine offer a compelling data-driven perspective, suggesting that a move to permanent standard time could foster a healthier, more synchronized population by better aligning with our innate biological rhythms.