Do you need more sleep in fall and winter? Probably.
It’s a crisp fall day in mid-November, and even though your calendar is filled with evening meetings and morning runs, you’re feeling lazy. All you really want to do is sleep or curl up on the couch and take a nap. Are you lazy or do you really need to sleep more as the temperature drops and the amount of daylight decreases? The answer is not so clear.
“I don’t think we need more sleep as the days get shorter, but people often feel sleepier,” says Dr. Karin Johnson, a sleep medicine specialist and spokesperson for the American Academy of Sleep Medicine (AASM), a global network of sleep medicine specialists that advances sleep health worldwide.
Reasons we feel more lethargic in winter and fall
Overall, we naturally tend to sleep more in the winter and when the weather typically gets colder in the fall. Johnson thinks there are several theories as to why. “The first is that when the days are shorter, our melatonin levels are higher,” she says. Melatonin is a naturally produced hormone that regulates our sleep-wake cycle. But consuming too much can make us sleepy and lower our energy levels, leading us to want to sleep longer.
“The other is that there are more disruptions in our circadian rhythm,” the body’s natural 24-hour clock that regulates our sleep-wake cycle. As daylight hours decrease, our circadian rhythm changes. This can disrupt our sleep schedules and lead to excessive fatigue. “Especially if we don’t have enough morning light.”
We tend to spend more time indoors in the winter than in the warmer months, which means less natural light. This disconnects us from the rhythms of nature and can alter our natural sleep patterns. When mornings are dark, it’s harder to get out of bed because morning sunlight helps regulate the circadian rhythm and signals our bodies to wake up.
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REM sleep in winter
Data published in 2023 in the scientific journal Frontiers of neuroscience shows that people experience longer REM sleep (the fourth and final stage of the sleep cycle, when most dreams occur) in winter than in summer. REM sleep is essential for brain health, mood regulation, and mental clarity.
Although humans don’t hibernate like animals, we tend to go into hibernation mode when the seasons change: we slow down, eat larger foods, and overall feel more lethargic. Our bodies also compensate for less sunlight by giving us more REM sleep.
The roles of temperature and food in sleep
“In general, people sleep better when it’s cooler,” says Johnson. However, if it’s cold outside and we turn up the heat, then we might become even more sleepy. Our bodies also work harder to conserve heat when it’s cold, which can cause “winter fatigue” and make us more groggy.
We tend to eat heavier, higher-carb foods (called “comfort foods”) in the winter, which can lower our overall energy levels since these types of meals take longer to digest. With less energy, we are also inclined to exercise less. It’s almost a ripple effect.
Seasonal Affective Disorder (SAD)
About five percent of adults in the United States suffer from seasonal affective disorder (SAD), symptoms of depression that occur during the winter months. SAD is linked to a decrease in sunlight which, in addition to increasing melatonin levels and disrupting our circadian rhythms, also reduces the amount of serotonin – a natural mood enhancer – produced by our bodies. Drowsiness is often a common symptom.
Seasonal affective disorder (SAD) affects approximately five percent of adults in the United States.Video: Seasonal Affective Disorder, Mayo Clinic Health System
How to deal with winter gloom
In short, even though our bodies don’t biologically need to sleep more in winter, changes in daylight, diet, temperature, and mood often make us want to stay in bed longer. Which is good. The trick, Johnson says, is to stick to a schedule.
“Sleep when it feels natural. Wake up when you feel rested,” she says. “Just make sure you prioritize sleep time, which a lot of people don’t do.” Johnson emphasizes the importance of morning light in following our daily routines. “If you don’t have that natural light exposure, using a light box for about 30 minutes each morning can be very helpful.”
Since most people’s waking time is usually out of our control due to school or work schedules, Johnson says going to bed earlier in the winter could help accommodate human seasonality. “Try to turn off electronic devices in the evening, keep a regular meal schedule during the day, and make sure you get a good amount of physical activity.” It’s all about adapting to the season as much as possible, which might just mean getting more sleep.
And really, what’s so bad about an extra hour or two of zzz’s?
This story is part of the Popular Science book Ask Us Anything Serieswhere we answer your craziest and most burning questions, from the ordinary to the unusual. Do you have something you always wanted to know? Ask us.
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