What Sleep Docs Want You to Know About Turning the Clocks Back and Shorter Winter Days

Before heading to bed on November 5, many Americans will set their clocks back one hour to prepare for the end of daylight saving time (DST). In the states that change clocks (Arizona and Hawaii are the only U.S. states that do not), the time always gets set back an hour on the first Sunday in November, according to the U.S. Department of Transportation. This year DST officially ends at 2 a.m. on Sunday, November 6.

This practice of moving the clocks forward in the spring and then back to standard time in the fall (remember: fall back, spring forward) was originally conceived to optimize natural daylight hours, according to The Old Farmer’s Almanac. The United States, however, adopted the practice during World War I for energy conservation — this is contrary to the misconception that DST was supported by farmers, who actually raised objections to such changes.

If you find yourself rejoicing each year over the extra hour of sleep, we hear you.

But some medical experts say the extra slumber may actually have some unintended consequences on our health. As of March of this year, 28 U.S. states have introduced legislation to abolish DST all together, according to The Old Farmer’s Almanac.

Also in March of this year, the U.S. Senate approved a bill, which if passed by the U.S. House of Representatives and signed into law by the President, would make DST permanent starting in November 2023 (the Sunshine Protection Act), leaving clocks permanently in “spring forward” mode.

And it’s worth noting that while many sleep experts are in favor of getting rid of the time change permanently, the American Academy of Sleep Medicine (AASM) opposes the idea of making daylight savings time the permanent time. In a position statement from earlier this year the organization noted its support for the adoption of year-round standard time (or winter time), which aligns better with human circadian biology and provides distinct benefits for public health and safety.

Here’s what you should know about the science behind why the biannual time change may not be so great for health and some tips for easing the transition since — for now, at least — DST is happening.

Changing the Clocks on the Walls Can Throw Off Our Body Clocks

Setting the clock back affects your body’s circadian rhythms — the physical, mental, and behavioral changes in your body that follow a 24-hour cycle, according to the National Institute of General Medical Sciences (NIGMS) definition.

Our bodies expect certain things to happen at certain times during the day (like sleeping, waking up, and eating) based on cues from the sun and on your doing those things over and over again at the same time every day. For example, says Aneesa Das, MD, a sleep medicine specialist at The Ohio State University Wexner Medical Center, “natural sunlight during the day and the absence of light in the evening help to drive our circadian sleep phase.”

RELATED: Everything You Need to Know About Your Circadian Rhythm and How It Affects Your Sleep

When you shift that routine — even by an hour — your circadian rhythms gets slightly thrown off, similar to the effect of jet lag (according to a review published in 2019 Frontiers in Physiology). The result: Your circadian rhythms become slightly misaligned from the time on the clock, which can throw off the timing of several daily processes that happen in the body (like sleep, digestion, and cardiovascular functioning).

And while many people may not feel all that individually affected by the change, large-scale data suggests that health problems like heart attacks and accidents may increase because of the change to and from DST, the aforementioned review concludes.

Research published in April 2020 in Sleep that followed healthcare workers for eight years revealed an 18 percent uptick in safety-related human errors in the week following DST in the spring and a 5 percent increase in the fall. (The data was preliminarily published as an abstract; it was presented at SLEEP 2020, a joint virtual meeting of the American Academy of Sleep Medicine [AASM] and Sleep Research Society.)

Another study, published in 2018 in the Journal of Biological Rhythms, found general accidents and emergency room visits increase significantly after the start of DST in the spring (though decreased slightly directly after the end of DST in the fall).

And a seven-year survey of Russian children and adolescents published in August 2016 in the journal Biological Rhythm Research found that DST had a negative effect on sleep habits, mood, and behavior.

Any disruption in the sleep or circadian cycle has the potential to increase risk of disease, says Matthew Morgan, MD, a primary care physician at Ochsner Health Center in Chalmette, Louisiana. Changes in daylight patterns — like the shorter days during fall and winter months — also affect your body’s normal sleep-wake cycle.

But those changes happen gradually over the fall months as the days get shorter (particularly in places farther north). DST clock changes happen overnight. “It can take several weeks for your circadian rhythm to adjust to the change that the end of DST brings," adds Whitney Hardy, MD, a family medicine physician at Ochsner Health Center in Marrero, Louisiana.

If you’re a night owl, take note: In a study published in July 2021 in the journal Scientific Reports, University of Michigan researchers found that those who prefer to stay up later at night fared worse during the “spring forward” compared with their early bird counterparts. Night owls could take more than a week to get back on track with their sleep schedules, they suggested.

Misaligned Body Clocks Can Up Risk of Seasonal Depression

Another problem with shifting the clocks is that any sudden changes in sleep and daylight exposure can increase mood changes and risk of seasonal affective disorder (SAD), too, Dr. Morgan says.

SAD is a form of depression that follows a recurring seasonal pattern, according to the National Institute of Mental Health (NIMH). And even for people who don’t have the more severe symptoms associated with depression (decreased interest in work, friends, or hobbies; insomnia; dramatic changes in appetite; feeling worthless or empty; suicidal thoughts; and others), estimates suggest that a lot of people experience these mood changes to a lesser extent with symptoms like sad mood, low energy, trouble concentrating, weight gain, and increased cravings for carbs — more commonly referred to as the “winter blues.”

RELATED: 12 Way to Ease Seasonal Depression Symptoms

SAD typically strikes during the fall and winter months, when daylight hours are shorter, Morgan says. Danish researchers reported data that suggested depressive episodes increased by as much as 11 percent following the fall setting back of the clocks. Their findings were published in May 2017 in Epidemiology.

5 Tips for Making the Transition Easier on Your Body

The good news is that you can minimize the effects of shorter days after the DST ends this fall. Try following these tips:

1. Start With Basic Sleep Hygiene

Practicing healthy sleep habits is important no matter what time of year it is, Morgan says. If you’re already sticking to a consistent sleep routine, you’re less likely to be affected by the hour switch than if you’re regularly shifting sleep and wake times from day to day.

Going to bed and waking up at the same time every day, using your bed only for sleep and sex, avoiding caffeine in the late afternoon and evening, and limiting bright light exposure in the evenings (turn off electronic devices at least 30 minutes before bed) can all help establish a consistent sleep routine, according to the American Academy of Sleep Medicine (AASM).

“Relaxing activities, such as reading in a different room or going for a walk, before bed can also be of benefit,” Morgan says.

The end of DST may offer a good opportunity to reevaluate your sleep habits and figure out how to improve them, says Jamie M. Zeitzer, PhD, an associate research professor at the Stanford Center for Sleep Sciences and Medicine in Palo Alto, California. “Kind of like a New Year’s resolution, [DST] is a good excuse to do something about your sleep.”

2. Don’t Procrastinate When It Comes to Changing the Clocks

To make the time change feel more natural, Dr. Hardy suggests setting all the clocks in your home back the night before the switch. This way, when you wake up, you’ll be prompted (by your clocks) to start adjusting to the new time right away (and a day ahead of the start of the workweek on Monday, when you might be more likely to be affected by being thrown off schedule).

As you adjust to the time change that first week, it may be tempting to take naps or sleep in on the weekends, but do your best to stick with your regular sleep schedule as best as you can. If you feel like you must take a nap, the Cleveland Clinic suggests taking one earlier in the day for 20 minutes max.

3. Get Natural Sunlight in the Morning for Better Sleep and Mood

Natural sunlight plays a key role in regulating mood and sleep-wake cycles. In particular, getting sunlight first thing in the morning helps tell your body it’s morning and it’s time to be awake, helping you realign your body’s circadian rhythms to the new non-DST time, according to Dr. Zeitzer.

One study, published in June 2017 in Sleep Health, found that office workers who received higher levels of sunlight in the morning during winter months reported better sleep quality, lower levels of depression, and reduced sleep-onset latency (the time it takes to fall asleep once your head hits the pillow) compared with office workers who received lower levels of sunlight.

A U.K.-based longitudinal study published in August 2021 in the Journal of Affective Disorders came to a similar conclusion. After studying data from 400,000 participants, researchers found that each additional hour people reported spending outdoors during the day was tied to lower odds of depression, antidepressant usage, and low mood. More time spent in daytime light was also linked to greater ease with getting up in the morning and less frequent tiredness throughout the day.

Exposure to light through your windows helps, too, Zeitzer says. Think about repositioning a desk (if you can) or the table where you eat breakfast.

4. Consider Light Therapy as a Stand-In for Natural Sunlight

If you typically wake up before sunrise, or you have a hard time getting outdoors, consider using light therapy as a stand-in for natural sunlight, Zeitzer says. It involves the use of a light therapy box, a small device that emits a type of artificial light shown to mimic outdoor light.

When used in the morning (typically, right after you wake up, the Mayo Clinic notes), light therapy can signal to your body that it’s time to be awake, helping kick-start your internal clock so it aligns with the clock on your phone, according to a review published in 2019 in Somnologie. And remember, realigning your internal clock is especially important right after the end of DST.

For maximum effectiveness, use the light box for about 20 to 30 minutes within an hour of waking up every day, making sure to sit about 16 to 24 inches away from the box, suggests Mayo Clinic.

5. Use Exercise to Boost Mood and Energy

Exercise releases natural feel-good chemicals in your brain that can boost your sense of well-being and helps distract you from negative thoughts that may dampen your mood, according to Mayo Clinic. It’s why exercise helps boost energy levels, which help you cope with some of that extra fatigue you might be feeling, given the shortage of sunlight and new time, Hardy says.

In addition to light therapy, aerobic exercise may also help lessen mood changes (and depression symptoms) tied to the change of seasons and our body clocks being slightly misaligned, according to a past review. Exercise is associated with an uptick in neurotransmitters and proteins called neurotrophic factors, which are thought to lessen symptoms in people with depression, research suggests.

Just note that exercising too close to bedtime may interfere with sleep (by blocking the release of melatonin, the hormone that signals to your brain it’s time to sleep). For this reason, it’s best to avoid any heavy workouts within a few hours before your regularly scheduled bedtime.

With additional reporting by Kristeen Cherney.