Sleep Experts Call for End to Daylight Saving Time

woman hitting snooze on her alarm clock

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Key Takeaways

  • The American Academy of Sleep Medicine has released a position paper calling for the end of daylight saving time for health-related reasons.
  • Although daylight saving time is an adjustment of just an hour, it can have profound effects on wellness, experts suggest.
  • There are several strategies that can help you adjust faster, such as going outside more and exercising regularly.

Although it's only an adjustment by one hour each spring and fall, daylight saving time (DST) has such a profound effect on sleep and health that the American Academy of Sleep Medicine (AASM) has just released a position paper calling for eradication of the practice.

Contributors to the statement note that there is ample evidence to indicate the switch from standard time to DST every spring brings significant public health and safety risks, including:

  • Adverse cardiovascular events
  • Mood disorders
  • More motor vehicle crashes
  • Metabolic syndrome incidence
  • Sleep problems

As a result, the AASM has called for seasonal time changes to be "abolished in favor of a fixed, national, year-round standard time," according to the position paper.

Why Do We Have Daylight Saving Time?

First proposed in 1895 by New Zealand entomologist George Hudson who saw the value in utilizing daylight more effectively for research, and then again in 1905 by William Willet, an English outdoorsman who disliked having to cut his golf game short at dusk, DST was implemented in 1916 in Germany and then in the U.S. two years later.

Other countries began changing to the system around the same time, but some never did. For example, many parts of Asia and Africa don't use DST, and some countries have tried the system and then later went back to standard time—Russia, for instance, discontinued its use in 2014.

The practice has been a source of controversy since the beginning, with supporters claiming that it saves energy and heating costs, and encourages people to get outside for longer stretches of time. But detractors, like the current AASM contributors, believe it has more health impacts than most people realize and can be particularly tough on the body's natural circadian rhythms.

Getting Out of Rhythm

The type of internal clocks used by humans—as well as animals and even plants—influence numerous physiologic processes, according to Madelyn Rosenthal, MD, sleep medicine expert at The Ohio State University Wexner Medical Center. In people, these include:

  • The sleep-wake cycle
  • Hormonal activity
  • When we eat
  • Cognition performance
  • Body temperature
  • Digestion
  • Mood

Madelyn Rosenthal, MD

Sunlight and the darkness of night provide cues to adjust the internal clock. But our bodies also receive input from the 'social clock,' which can be thought of as the measure of time set by humans.

— Madelyn Rosenthal, MD

According to the recent position paper, there's even been volatility in U.S. stock markets the Monday after the transition to DST, although the reasons aren't entirely clear. However, researchers have suggested it could be an impact of sleep deprivation, which could have an effect on judgment and decision-making capacity.

Internal and External Clocks

The main cue influencing rhythms is daylight, which can turn on or off genes that control the function of this internal timing mechanism.

"This internal clock must align closely with the 24-hour 'environmental clock,'" says Rosenthal. "Sunlight and the darkness of night provide cues to adjust the internal clock. But our bodies also receive input from the 'social clock,' which can be thought of as the measure of time set by humans."

DST resets the social clock, Rosenthal says, but that can throw us out alignment with the environmental clock. She notes that research has shown this change can lead to insomnia, decreased cognitive performance, and increased heart attacks.

Alex Dimitriu, MD

Beyond sleep and wake time, the loss of daylight in the afternoons, especially in the winter, makes it harder to exercise or spend time outdoors, which can both be beneficial to mood or nighttime sleep quality.

— Alex Dimitriu, MD

For many people, another issue is that it takes more than a few days to adjust, adds Alex Dimitriu, MD, founder of Menlo Park Psychiatry & Sleep Medicine.

"In my practice, issues like insomnia, depression, and anxiety often get worse around the shift in daylight saving, and it can take people up to two or three weeks to fully adjust to the transition," he says. "Beyond sleep and wake time, the loss of daylight in the afternoons, especially in the winter, makes it harder to exercise or spend time outdoors, which can both be beneficial to mood or nighttime sleep quality."

Tips for Realignment

Obviously, changing DST is not a high priority for Congress right now. But until it does come up for legislative efforts, there are shifts you can make to get the kind of alignment Rosenthal suggests, which would lower your risk for health issues. She suggests:

  • Expose yourself to more bright light in the morning and early afternoon
  • Avoid bright light in the late afternoon and evening as this will delay your body’s internal clock—this includes artificial light such as TVs, computers, overhead lighting and lamps
  • Consider use of dimmers for artificial lights in your house in the evening
  • Be strict and stick to your schedule
  • Consider use of a sunlight simulating alarm clock particularly if you have to wake up before the sun comes up in the winter time
  • Try to avoid napping
  • Avoid caffeine in the afternoons
  • Exercise at least a few hours before bedtime

Most importantly, spend time outside, Dimitriu adds. The fresh air—even if it's cold—and natural sunlight can help you adjust, and get sleep quality back on track.

9 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Rishi MA, Ahmed O, Barrantes perez JH, et al. Daylight saving time: an American Academy of Sleep Medicine position statementJ Clin Sleep Med. 2020. doi:10.5664/jcsm.8780

  2. Waxman OB. TIME. The Real Reason Why Daylight Saving Time Is a Thing.

  3. Gharib M. NPR. Much Of The World Doesn't Do Daylight Saving Time. How Come?

  4. Potter GD, Skene DJ, Arendt J, Cade JE, Grant PJ, Hardie LJ. Circadian Rhythm and Sleep Disruption: Causes, Metabolic Consequences, and Countermeasures. Endocr Rev. 2016;37(6):584-608. doi:10.1210/er.2016-1083

  5. National Institute of General Medical Sciences. Circadian Rhythms

  6. Roenneberg T, Winnebeck EC, Klerman EB. Daylight Saving Time and Artificial Time Zones - A Battle Between Biological and Social Times. Front Physiol. 2019;10:944. doi:10.3389/fphys.2019.00944

  7. Tosini G, Ferguson I, Tsubota K. Effects of blue light on the circadian system and eye physiology. Mol Vis. 2016;22:61-72.

  8. Dolezal BA, Neufeld EV, Boland DM, Martin JL, Cooper CB. Interrelationship between Sleep and Exercise: A Systematic Review. Adv Prev Med. 2017;2017:1364387. doi:10.1155/2017/1364387

  9. Blume C, Garbazza C, Spitschan M. Effects of light on human circadian rhythms, sleep and mood. Somnologie (Berl). 2019;23(3):147-156. doi:10.1007/s11818-019-00215-x

By Elizabeth Millard
Elizabeth Millard is a freelance journalist specializing in health, wellness, fitness, and nutrition.