It’s not official by the calendar yet, but with the time change behind us and wintry weather across sections of the U.S., we’re already well launched into the winter season. Like any other time of year, winter can bring both enhancements and challenges to a healthy sleep routine. Short days and long nights can make for cozy, quiet, restful evenings. For many people, the quick pace of the fall quiets down a bit during winter, helping us slow down and relax.
But there are also pitfalls to watch for. The extended darkness leads to changes in circadian rhythms, which can throw our sleep routines off course, and leave us feeling sluggish, low-energy, and tired—even after a long night spent in bed. Millions of people, particularly those in the northern areas of the U.S., cope with wintertime Seasonal Affective Disorder, which can have a significant negative impact on sleep and mood, as well as appetite and energy levels for things like exercise.
The key to sleeping well in winter? Know what to watch for in changes to your sleep. Know the daily habits—both good and bad—that are likely to affect your ability to rest at night. Here are my top sleep tips for the season: the most important things to pay attention to this winter, for sleeping well right through until spring.
Don’t wind down too early
We’re headed toward the shortest day of the year, December 21st’s winter solstice. Much of the country is experiencing significantly less daylight. Thanks to November’s clock shift backward, darkness sets in for many of us particularly early, according to social time.
The degree of the darkening of wintertime depends on where you live. If you’re in the northern part of the continental U.S., you’re experiencing as little as 8 hours of daylight around the winter solstice. The southern stretch of the country will get as much as an additional 2.5 hours of daylight, even on our shortest day. And Alaskans will have to make do with no more than 6 hours of daylight—and often much less—by the time the solstice arrives.
The curtailment of daylight means big changes for our bodies, which rely on light and darkness cues to regulate our bio clocks. That includes the production of melatonin, a key hormone facilitating sleep. With so much time spent in darkness, melatonin production—which is triggered by the absence of light—becomes extended. For some people, these circadian shifts can lead to winter depression, and seasonal affective disorder. If you experience low mood and other symptoms of depression or SAD, talk with your doctor.
It’s very easy to begin shifting into lower gear earlier in the evening, and many people just go to bed earlier and stay in bed longer during the winter months. But your sleep and health are best served by sticking to your standard (hopefully consistent!) routine of sleep, rather than extending your sleep time in the depths of winter. You’ll keep your circadian rhythms ticking in sync. And you’ll avoid the hazards of oversleeping, which often get overlooked—but are very real. (I wrote recently about the psychological, cognitive and physical effects of oversleeping.)
A modest change to your sleep routine in winter is fine. I recommend a slightly earlier bedtime, while keeping your wake time the same—and starting your day off with some bright light to get you rolling! (More on that in a minute.) Try to keep any changes to your winter sleep schedule within 30 minutes of your rest-of-year habit.
Keep up with exercise
This is an evergreen tip for sleep. There’s no time of year when exercise and physical activity isn’t a good thing for your nightly rest. But exercising during the winter months can be particularly helpful to sleep. Exercise is a natural therapy for depression, one that research shows works as well—or better—than antidepressant medications, without the potential side effects (which include disruptions to sleep). Staying physically active can reduce the symptoms of SAD. And the routine of exercise can help strengthen your circadian rhythms, which will keep you sleeping, eating, and feeling more like yourself during these winter months.
Timing your exercise right during winter can expand its benefits. If you’re struggling to get moving in the mornings, try a workout first thing. Even a short one can make a big difference for your day. If you’re finding yourself tempted to crawl into bed right after dinner, consider scheduling exercise for the very late afternoon or early evening. This will send a message to your bio clock and body that it’s time to keep alert and active for another few hours.
Know your Vitamin D
Our most potent source of Vitamin D? Sunlight. That’s why so many people—especially those in northern areas of the U.S.—suffer from low levels of Vitamin D during the winter. Across the country, an estimated 50 percent of adults and kids have a Vitamin D deficiency.
Research has shown that in addition to its other benefits for health (stabilizing mood, supporting healthy bones, strengthening immune function), Vitamin D also enhances sleep. Studies show a lack of Vitamin D reduces sleep time and lowers sleep efficiency—that’s an important measurement of sleep quality. For many people, winter is the time we’re most likely to be deficient.
If you don’t already have your Vitamin D levels assessed as part of your physical, ask your doctor to perform that blood test. This is particularly useful for people in northern climates, or anyone experiencing symptoms of Vitamin D deficiency, including tiredness, pain and stiffness in bones and muscles, and an overall feeling of being under the weather. Once you know where you stand, you can work with your doctor to elevate your levels, using supplements as well as controlled sun exposure and dietary modifications.
Here’s my rundown on Vitamin D, it’s importance to sleep, and how you can raise your levels.
Watch the nighttime snacking
Is there another time of year when nighttime snacking is more tempting than the middle of winter? I don’t think so. I’m a nighttime snacker by nature (most of us Wolf chronotypes are), and these dark, quiet winter evenings are the toughest!
It’s worth it, for your waistline and your nightly sleep routine, to avoid the winter evening snackfest. Having to digest a large amount of food will keep your body from transitioning into sleep mode. Eating and digestion send messages to your body’s bio clock, altering circadian rhythms. Our bodies face enough circadian challenges during winter without having to receive mixed messages from a late-night eating habit. And as we know, we’re more likely to gain weight when we shift more of our calories to the evening hours.
You can have a light snack at night. Just don’t overdo. Aim for about 200 calories maximum, with a mixture of complex carbohydrate and protein, and a limit on the sugar. My favorite nighttime treat? NightFood bars. They’re delicious, and they’re formulated specifically as pre-bedtime treat that won’t interfere with your sleep. I always keep them in our house, and they do the trick for me, keeping me away from the junk-food treats I crave at this time of year.
Tend to your gut health
Nightly trips to the junk-food cabinet aren’t the only dietary challenge we face during winter. The holidays are here, with their offerings of rich, indulgent foods we don’t typically eat. The winter season causes changes to appetite that send us toward heavier, more sugar- and carbohydrate-rich foods. Our daily calorie intake goes up during the winter months. We experience seasonal changes to our hunger hormones. Levels of the hunger-stimulating hormone ghrelin go up in winter, while levels of leptin—the hormone that produces feelings of fullness—go down.
Our heightened drive for carbs may have to do with carbohydrates connection to serotonin. Carbohydrates increase serotonin production. These winter cravings may be our body’s way of attempting to lift a low, winter mood.
All this takes a toll on our gut health. The health of the gut microbiome—the vast collection of micro-organisms in our intestines—is a hot topic, with good reason. The health of our gut affects our immune system, our moods, our brain function, and our overall wellness, according to a fast-growing body of research.
I’m deeply interested in the connection between our microbiome health and our sleep. I’m on the Scientific Advisory Board for UBiome, which is dedicated to learning and teaching about the human microbiome, and how we can keep it healthy.
Studies show there is a two-way street that runs between gut health and sleep. Not sleeping well causes an increase to unhealthful gut bacteria, and at the same time reduces beneficial bacteria. According to recent research, these negative effects can happen after just two nights of not getting enough sleep. Research also suggests that dysfunction in the microbiome may contribute to disrupted, unrefreshing sleep.
(Here’s the round-up of some of the newest research on the gut-sleep connection I wrote earlier this year.)
Not eating too heavily at night is one way to keep your gut healthy. Winter can also be a good time to focus on getting plenty of prebiotics. What are prebiotics? They’re an energy source (think: food) for the trillions of tiny organisms in your gut. High-fiber, plant-based foods are good sources of prebiotics. Prebiotics are also available in supplement form. Recent research indicates a prebiotic-rich diet can reduce stress and improve sleep.
Seek out sunlight (or any light)
This might be the most important tip on this list. Exposing yourself to light during daylight hours is so important to sleeping well and feeling well throughout winter. Light exposure first thing in the morning inhibit melatonin production and stimulates cortisol. These hormonal changes are a key element of the get-up-and-go response we all want to have in the morning, as opposed to the sluggish feeling that often accompanies the start of a winter day. At midday, the sun is the strongest—that’s another good time to get a dose of sunlight if you can. Soaking up light in the first part of the day will help your energy and mental function and lift your mood. It also will send powerful cues to your bio clock, helping to keep it in sync and on track. That translates into an easier time falling asleep at night, and more refreshing, restorative rest.
Of course, winter isn’t always the friendliest time to be outdoors. Use bright indoor lights to stimulate your wakefulness during morning and midday, as a supplement or an alternative to natural light. If you’re someone who experiences depression or seasonal affective disorder in winter, consider light therapy to help sleep and mood.
Stay warm at night—but not too warm
When we’re sleeping, our bodies lose some of their ability to regulate temperature. That makes us extra susceptible to the effects our sleep environment. The optimal temperature for sleep—about 65 degrees Fahrenheit—remains the same no matter the season. Keeping that nighttime room temperature in place can help ensure you won’t wake in the middle of the night because your room has gotten too cold.
Body temperature drops during the onset of sleep, and our bodies shed heat through our extremities—our hands and feet. Cold feet are one of the most common causes of nighttime awakenings in the winter!
Dedicate some warm socks for sleeping if you’re prone to having chilly toes at night. And be sure to dress yourself and your bedding in natural, breathable fabrics that allow heat to circulate and dissipate, so you don’t overheat from trying to keep yourself from being too cold.
We’ve got a long winter ahead of us. With a little planning and some daily attention, this season can be a restful one, full of relaxation and plenty of nourishing rest.
Michael J. Breus, PhD, DABSM
The Sleep Doctor