More daylight, less sleep: How to get ready for daylight saving time

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It happens every year, yet somehow, the switch to daylight saving time always catches people off guard. Losing one hour of sleep might not sound like much, but many struggle to adjust, waking up feeling groggy and fatigued. It’s just a one-hour difference after all, so why does this simple time change feel so hard on the body?

That loss of one hour of sleep doesn’t just make mornings a little harder — it can throw off sleep patterns and affect mood and overall health. Research has linked daylight saving time to increased fatigue, reduced focus and serious cardiovascular health risks.

Dr. Zhikui Wei, a sleep neurologist at Jefferson Sleep Clinic, says even a small time change can throw off the body’s internal clock.

“When the time is moved forward by one hour, there is a one-hour loss in sleep opportunity, and most adults because they are not able to adapt to the new schedule immediately, there is ongoing sleep loss,” he said. “That sleep loss can accumulate over weeks to months that lead to ongoing sleep debt.”

The human body relies on natural light to help regulate the sleep/wake cycle, also known as the circadian rhythm. When the clock moves forward for daylight saving time, the darker mornings can disrupt the body’s natural rhythm.

“Light is the most important cue to train the circadian rhythm, so when the time is moved one hour forward, then that causes misalignment between the biological clock and the natural day and night cycle”, Wei says.

Individuals with poor sleep habits or circadian rhythm problems are especially vulnerable to the negative effects of the time change, with teenagers being among the most affected.

“Teenagers, they have a bilateral drive to go to bed later and wake up later,” said Wei. “They also have to wake up early to go to school, which makes the sleep loss even more significant for them.”

The disruption doesn’t just lead to sleep loss — it can have a wide range of effects on a person’s behaviors, productivity and overall health. “I think it all comes down to that sleep is just closely linked with our overall function, our mood, our health. Patients or adults who suffer from poor sleep can have lower daytime function or productivity”, Wei said.

Some studies have shown a link between daylight saving time and increased cardiovascular health risks. Wei says there’s an increased incidence of heart attacks, strokes and emergency room visits after the switch.

Wei adds that losing an hour of sleep can also take a toll on mental health.

“We tend to see that patients who have poor sleep also have mental health problems and the relationship goes the other way too … In transitioning from the standard time to daylight saving time, we do see higher incidence of anxiety and depression.”

Given the significant impacts on physical and mental health, taking proactive steps to ease the transition can improve the body’s adjustment.

Wei encourages people to prepare for the transition, ensure they get 7–9 hours of sleep, and be mindful of their sleep schedules.

He says going to sleep earlier in the days leading up to daylight saving time can help with the transition. “If people can go to bed maybe 10, 15 minutes earlier each day to gradually let themselves get used to the new schedule and wake up 10, 15 minutes earlier each morning … that’ll probably be helpful to minimize some of their disruptions.”

There’s a push to make daylight savings time permanent, but Wei is in favor of adopting standard time year-round. “The medical community in general have voiced support for the permanent standard time, including myself,” Wei said. “Standard time ensures that our circadian rhythm is better aligned with a natural daylight cycle. So just to ensure the better alignment of our endogenous rhythm with a natural daylight cycle, I think the permanent standard time is definitely strongly favored among the medical communities.”

While the future of daylight saving time remains uncertain, taking small steps to prepare can make the transition easier and minimize its impact on sleep patterns and overall health.