by Mary Spiller
November 1, 2025
New Stanford research says the twice-a-year time switch may affect our healthy — and permanent standard time may be best.
As clocks shift back an hour at 2 a.m. Nov. 2, millions of Americans will enjoy a rare bonus hour of sleep. But experts say the seasonal switch from daylight saving time to standard time does more than change when the sun rises — it also disrupts the body’s internal clock in ways that can affect sleep, mood, and overall health.
“Plan on a glorious extra hour of sleep as most of America ‘falls back’ into standard time,” the article notes, adding that morning sunlight can help the body reset its internal rhythm more smoothly. Standard time will remain in place until March 8, when clocks jump forward.
The twice-a-year shift has long been debated, but a new Stanford University study argues that the current back-and-forth system is the worst option. Researchers found that adopting either permanent daylight saving time or permanent standard time would improve health — but standard time aligns more naturally with the body’s biology.
“The best way to think about it is as if the central clock were like a conductor of an orchestra,” said Jamie Zeitzer, co-director of Stanford’s Center for Sleep and Circadian Sciences. “More light in the morning and less at night is key to keeping that rhythm on schedule — all the instruments in sync.”
When that rhythm is disrupted, Zeitzer said, each system of the body “just works a little less well,” from metabolism to immune function.
Groups like the American Medical Association and the American Academy of Sleep Medicine already support making standard time permanent, saying it better matches natural light patterns.
The spring transition — which takes an hour away instead of adding one — is widely seen as more difficult. Studies have linked the early March time jump to spikes in car crashes, heart attacks, and sleep loss. But even the November shift can affect those already struggling with limited sleep or working outside a traditional day schedule.
About one in three U.S. adults sleep less than the recommended seven hours a night, and more than half of teenagers fall short of the recommended eight hours.
As debate continues in Congress, where the stalled Sunshine Protection Act proposes making daylight saving time permanent, experts suggest easing into the change gradually — shifting bedtime by 10–15 minutes in the days before the switch, and getting sunlight early in the day.
“If you can’t get outdoors, sit by windows,” the article advises, noting that morning sun remains the most effective reset tool for the body’s natural clock.
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