Too Late to Bed, Too Early to Rise: How to Fix Poor Summer Sleep

Summer solstice celebrations this week — from Santa Barbara to Stone Henge — served as a potent reminder that all of us (sleep specialists included) sometimes willingly sacrifice part or all of a night’s sleep. That’s a personal choice.

Most Americans also are victims of an insidious sleep thief. Daylight saving time cuts sleep short every night for nearly eight months of the year.

From the second Sunday in March to the first Sunday in November, residents of every state except Arizona and Hawaii advance their clocks to daylight saving time, an hour later than standard time. Seven states see sunset pushed past 9:30 p.m. by daylight saving time, with twilight lasting past 10 p.m.

While sunset in summer naturally occurs later than in winter, daylight saving time amplifies the difference. The extended evening light exposure makes it harder to fall asleep. Daylight saving time squeezes the amount of time available to sleep, according to Jay Pea, founder and president of Save Standard Time, a nonpartisan national nonprofit.

Adults who arise at their usual time for work, school or caregiving responsibilities may get 19 minutes less sleep on average every night in the eight months governed by daylight saving time than they do while living on standard time, according to a 2019 report in the Journal of Health Economics.

Late sunsets make it especially hard for teens to fall asleep early enough to get the 8-to-10 hours of sleep per night that sleep specialists recommend. Sleep loss makes both adults and children feel sleepier and perform less capably and safely in the daytime than they do when better rested.

Year-round daylight saving time, as proposed by the deceptively named Sunshine Protection Act of 2023 that Sen. Marco Rubio (R-Fla.) introduced into Congress in March, would create another problem six months from now at the winter solstice. It would make winter’s late sunrises even later, dooming our already sleep-deprived nation to even greater sleep debt.

Daylight is the body’s most potent time-setting cue, and morning is the most important time to see it. Morning daylight regulates our daily sleep/wake cycle, mood, appetite, blood pressure, body temperature and hundreds of other bodily functions. Eating meals at the same times every day and regularizing times for exercise and other activities can help anchor our rhythms to the 24-hour day, but none of these activities works as effectively as sunlight to keep body clocks on schedule.

Extending daylight saving time into the winter would push sunrise past 8 a.m. in most of the country, meaning most Americans would start their days in the dark for two to three months. Unless you remember the dark winter of 1974 — the last time the U.S. briefly attempted permanent daylight saving time — you likely aren’t aware of how severely the loss of morning light harms sleep, mood and overall well-being. Public distress over long winter mornings halted the planned two-year experiment after just eight months.

Some people attempt to make up for lost sleep during the week by sleeping late on weekends. This practice typically makes it harder for many of them to fall asleep and wake up on weekdays. The mismatch between schedules on weekdays or workdays and those on weekends or free days produces what sleep specialists call “social jet lag.” Unlike the temporary jet lag that comes from flying across time zones, social jet lag persists.

On standard time, our body clocks stay in sync with the sun. During the eight months that most of the nation observes daylight saving time, body clocks never fully adapt to the time our external clocks display. We just muddle through.

The nation’s health would suffer on permanent daylight saving time, too. Dozens of studies link seasonal time changes to increased heart attacks, strokes and other medical problems, as well as increased hospital admissions, medical appointments, emergency room visits and return hospital visits.

Traffic fatalities in the U.S. rise 6% in the week after the transition to daylight saving time in the spring, particularly in westernmost parts of time zones with the latest sunrises, according to a 2020 study of more than 700,000 fatal motor vehicle crashes in all states observing daylight saving time between 1996 and 2017, reported in Current Biology. The study found afternoon rush-hour crashes did not fall, despite added daylight at that time of day.

The U.S. economy loses the equivalent of 1.23 million working days from insufficient sleep annually, harming corporate bottom lines in myriad ways, according to Christopher Barnes, a professor of management at the University of Washington Foster School of Business. “Healthy sleep is good for business,” he wrote in a 2019 report in Sleep Medicine Reviews.

Convinced by the weight of scientific evidence, the American Medical Association, American Academy of Sleep Medicine, as well as nearly 100 other health and community organizations have endorsed year-round standard time. Standard time is what we currently experience only from November to March.

Legislation proposed in 18 states this year urges the adoption of year-round standard time. The nation should embrace that option. Then we could all live as nature designed: in sync with the sun.

Karin Johnson, M.D., is a professor of neurology at the University of Massachusetts Chan Medical School-Baystate and medical director of the Baystate Health Regional Sleep Program. She is vice-president of the nonprofit nonpartisan Save Standard Time and creator and host of its new educational video series, “The Science of Clock Change.” She received an unprecedented three awards for community service at the Associated Professional Sleep Societies 2023 national meeting earlier this month.

Lynne Lamberg is a medical journalist and editor who writes frequently on sleep, biological clocks and mental health. She is the book editor of the National Association of Science Writers.