A new study published in the Proceedings of the National Academy of Sciences has shown that switching to permanent standard time could save millions of Americans from serious health risks such as strokes and obesity. Switching clocks twice a year disrupts circadian rhythms and may have serious health consequences for Americans.
The study modelled the health impact of three different potential time policies on Americans: permanent standard time, permanent daylight saving time, and the current biannual shifting pattern. The study modelled the impact of each policy on circadian rhythm in different parts of the country as well and the long-term health impact of time changes. Previous studies have shown that there is an acute negative impact on health immediately after switching between standard time and daylight saving time, but this study sought to determine the chronic health impact of time switching policies.
The results showed that shifting the time biannually had a greater impact on circadian rhythm and a worse impact on health than either permanent standard time or permanent daylight saving time. Permanent standard time had the most positive potential impact on health; switching to permanent standard time could result in 300,000 fewer strokes per year and about 2.6 million fewer people having obesity. Permanent daylight saving time would also improve health outcomes, although it had about two thirds of the impact on stroke and obesity compared to permanent standard time.
The authors noted that permanent standard time had the most positive impact on health because it prioritizes consistent morning light, although the results varied based on a person’s chronotype and location within their time zone. Getting consistent morning light helps synchronize us to the 24-hour day, while inconsistent light weakens our circadian rhythm. This weakening of the circadian rhythm can ultimately lead to sleep disorders, metabolic problems, and increased risk of chronic conditions such as heart disease.
Sources: Proceedings of the National Academy of Sciences, Science Daily