The twice-yearly clock change could be putting millions of Americans’ health at risk, and a simple solution exists.
Story Highlights
- Stanford study links biannual clock changes to increased stroke and obesity rates.
- Permanent standard time could prevent 300,000 strokes annually.
- 2.6 million Americans may avoid obesity with time policy change.
- Debate continues without federal legislative action.
Health Impacts of Clock Changes
Stanford Medicine researchers have highlighted the adverse health effects of biannual clock changes, linking them to increased rates of stroke and obesity. Their study, published in the *Proceedings of the National Academy of Sciences* in September 2025, revealed that adopting permanent standard time could prevent approximately 300,000 strokes and reduce obesity in 2.6 million Americans each year. These findings provide compelling evidence against the continued practice of switching clocks twice a year.
Historically, daylight saving time (DST) was implemented to conserve energy during World War I and II. However, recent studies have documented spikes in heart attacks and accidents following DST transitions. As states periodically debate its merits, the discussion has intensified with mounting scientific evidence of its health risks. The current practice in the U.S. involves observing DST from March to November, disrupting sleep patterns and public health.
Stanford scientists reveal simple shift that could prevent strokes and obesity nationwide https://t.co/jLsTohqyWW #genetherapy #financial #lifesciences pic.twitter.com/SFbs8VqAng
— Chris Columbkille Biddle 🇺🇸🇮🇪 (@ChrisBiddle) September 17, 2025
Legislative and Public Debate
The study has sparked renewed debate among federal and state legislators, as well as the general public, over the best approach to time policy. Researchers, led by Jamie Zeitzer, advocate for permanent standard time, emphasizing its alignment with natural circadian rhythms. They argue that consistent time settings would minimize health disruptions, a stance echoed by health organizations and circadian rhythm experts.
Despite the compelling evidence, no federal legislation to enact permanent standard time has been passed. The debate continues, with some business groups favoring permanent DST for evening daylight, although health experts overwhelmingly support standard time. The political discourse over time policy reflects broader issues of public health, economic implications, and state versus federal authority.
Potential Benefits and Challenges
Implementing permanent standard time could significantly reduce healthcare costs by preventing strokes and obesity, leading to improved workforce productivity and student performance. However, achieving consensus and legislative action remains a challenge. The debate underscores the need for policymakers to prioritize scientific evidence and public health benefits over traditional practices and economic preferences.
As discussions continue, the Stanford study serves as a pivotal point in the ongoing debate, urging lawmakers to consider the potential health benefits of a permanent time policy. The public’s growing awareness and concern over health risks associated with clock changes may influence future legislative actions, signaling a shift towards prioritizing health and well-being over outdated traditions.
Sources:
Daylight Saving Time Tied to Higher Rates of Stroke and Obesity: Stanford Study Finds Permanent Standard Time Would Improve National Health
Permanent Standard Time Could Cut Strokes, Obesity Among Americans
Stanford Medicine News: Daylight Saving Time
Science Daily: Permanent Standard Time and Health
SFGate: Stanford Daylight Saving Time Health Study
