Is it true we need more sleep in the winter?

The question:

Do we need more sleep in the winter?

The science:

Most Americans say they sleep more in the winter, but experts say there is no conclusive evidence that the amount of sleep we need changes with the seasons.

“From what we know, our internal biological need for sleep is pretty constant,” said Jennifer Martin, a clinical psychologist and spokesperson for the American Academy of Sleep Medicine. “However, during certain times of year, it’s easier to sleep than it is at other times.”

In the winter, the average duration of sleep for Americans increases by 1.9 minutes on weeknights and 6.5 minutes on weekends, according to a study of sleep duration analyzing the 2003-2016 American Time Use Survey.

These increases in sleep in the winter may be explained by our bodies’ response to light, or the lack of it.

Our circadian rhythms — which run a roughly 24-hour cycle and tell us when to wake up, eat and go to sleep — are set by daily light exposure or the amount and timing of light our eyes see from the sun.

In the winter, fewer hours of sunlight in the Northern Hemisphere allow our bodies to produce melatonin earlier in the evening, for instance. Melatonin helps promote sleep, and this may make it easier for some people to fall asleep earlier in winter months.

Research shows it is also easier for some people to get more REM sleep in the winter.

A 2023 study of nearly 300 people with sleep disorders found that participants got about 30 more minutes of REM sleep — the portion of sleep where most dreaming occurs and is thought to be important in emotional processing — in the winter vs. the summer. Our circadian clocks are known to regulate sleep, and a shift in circadian rhythms in the winter may cause an increase in REM sleep, though the mechanism isn’t fully understood.

Whatever the reason, “we should embrace that,” said Beth Malow, a professor of neurology and pediatrics, and the director of Vanderbilt University’s sleep division. “We should take that signal that our bodies are giving us, respect it and try to get that extra sleep that our bodies are telling us to get.”

What else you should know:

Research shows sleep deprivation and deficiencies have been associated with an increased risk of dementia, depression, diabetes, heart disease, high blood pressure, obesity and all-cause mortality.

To know if you are getting enough sleep, check how you feel during the day.

“One way of looking at the word ‘need’ is that if you don’t get enough of it, you are going to show signs of deficiency,” said Norman E. Rosenthal, a clinical professor of psychiatry at Georgetown University School of Medicine.

Those who are getting seven to nine hours of consistent, quality sleep at night but are struggling during the day — feeling fatigued, irritable, having trouble concentrating — “those are all good indicators that perhaps you might need a little bit more sleep,” said Joseph Dzierzewski, a licensed clinical psychologist and the vice president of research and scientific affairs of the National Sleep Foundation.

The bottom line:

Sleep experts say that while we probably don’t need more sleep in the winter, it appears some people do get a few extra minutes of sleep and more REM sleep during the winter months.