A Stanford University study found that abandoning seasonal clock changes could significantly reduce stroke and obesity rates. A model covering 300 million U.S. residents compared three scenarios: standard time, daylight saving time, and switching twice a year.
According to the researchers’ calculations, ending clock changes and moving to permanent standard time would prevent more than 306,000 strokes and 2.6 million cases of obesity each year. Permanent daylight saving time also has a noticeable effect: 220,000 fewer strokes and 1.7 million fewer cases of obesity.
The effect is explained by the fact that the body’s biological clocks — circadian rhythms — work much better with stable time. Changing the time twice a year disrupts these rhythms, creating so-called circadian burden, which worsens metabolism, promotes overeating, and increases cardiovascular risks. The risks are small for any one person, but matter at the national level.
The study took into account not only medical indicators but also social and ethnic characteristics of the population. No statistically significant changes were found for other diseases. The authors emphasize that the model includes assumptions, but the overall trend is clear. Time reform could turn out to be no less effective than major government health-prevention programs.
