The changing seasons bring changes to our sleep, as a result of shifts in our environment, our biology and our behavior. Understanding the seasonal variations associated with sleep can help you anticipate and address seasonal sleep challenges, and ensure your sleep is consistently restful and restorative throughout the year.
We encounter the most significant seasonal upheavals to sleep during summer (and winter), when we experience extremes of temperature, as well as daylight-darkness intervals. As we move into summer, here are some special considerations.
Summer’s light blues
Summer’s long, sun-filled days contribute to delayed melatonin production, which can alter circadian sleep-wake cycles and cause problems with nightly sleep. You may experience symptoms of insomnia in summer related to prolonged sunlight and your body’s diminished melatonin production, including falling asleep later, waking up earlier and sleeping less overall.
What to do
Take steps to make sure you get time out of bright light a couple of hours before bedtime, so your body can make the melatonin it needs to bring about sleep. Indoors, protect the darkness of your bedroom from early dawn sunlight, with blackout shades or curtains, to prevent your body from jumping too early into suppressing melatonin and boosting cortisol and other hormones that stimulate wakefulness.
Exposure to natural light is linked to better sleep and lower levels of depression and stress. This is true year-round, but it’s never easier to get consistent exposure to sunlight in the morning, after you awake, than during the summer months. This morning dose of sunshine will help energize you for the day and make you more inclined toward sleep at night.
Hot, humid days and nights
High temperatures make it harder for the body to shed heat and cool itself. Steamy and humid nights cause people to wake more often during the night. Steamy temperatures also diminish time spent in slow-wave sleep and REM sleep. These sleep stages are when the body does critical work to rejuvenate, from repairing cells and strengthening its immune system to processing memory
And it doesn’t take a record-breaking heat wave to experience these negative effects on sleep. Even mild heat exposure can keep body temperatures higher, alter time spent in sleep stages, and make it harder to fall asleep and stay asleep.
What to do
An ideal sleeping temperature for most people is about 68 to 72 degrees Fahrenheit, with low to moderate humidity. In summer, that means nearly all of us will need to take steps to cool down and dehumidify our sleeping spaces in order to sleep comfortably:
Keep your bedroom cool throughout the day, to prepare for a comfortable night’s sleep
Use light and breathable natural fabrics like cotton and linen
Don’t overdress for sleep— and try sleeping in the nude.
There’s some very effective sleep tech available to help manage your body temperature and the microclimate of your sleeping space, including regulating the temperature of your mattress and using cooling technology to calm the mind and rest more comfortably.
Summer vacation sleep mentality
During summer it’s easy to get relaxed about sleep schedules. Pretty soon, those regular bedtimes and wake times that anchor your family’s sleep have flown out the window. That can set you up with an ongoing sleep deficit and upset the sensitive timing of circadian rhythms, which can have a cascading effect on your sleep, performance and mood. (Think: tired, distracted and cranky.)
What to do
Keep a consistent sleep schedule. That goes for weekdays and weekends—and for all the seasons of the year. Stick within 30-60 minutes of your regular bed and wake times, and you’ll spend the summer getting the rest you need and keeping your circadian sleep-wake rhythms on track. This goes for kids and teens, too. Work with them to keep their bedtimes and wake times within 60 minutes of their regular schedule, and they’ll be much less likely to get sleep deprived. Plus, the transition back to school will be less painful for everyone.
Michael Breus, PhD, is a double board-certified sleep specialist, founder of TheSleepDoctor. com, author of three books on sleep, including the latest, Energize! with Stacey Griffith, and has been in practice for 23 years.