Can’t fall asleep because of the heat? You’re not alone. Research has shown that how quickly a person falls asleep and how well they can stay asleep has a lot to do with their ability to thermoregulate, or keep their body cool. That hasn’t been an easy thing to do for much of the northern hemisphere this summer, with heat wave after heat wave bludgeoning our bodies and turning our sleep schedules haywire.
Rising nighttime temperatures around the world due to climate change are starting to push the upper limits of our thermoregulation: A May study of more than 47,000 sleepers found that warmer temperatures at night led to less sleep and more tossing and turning before falling asleep, a true double whammy. That same study predicted that by the end of the century, climate change could shorten our sleep spans by 58 hours per year. Horrifying!
So what can we do with this information, besides allowing it to keep us up at night while we sweat through our sheets? A new study run by researchers in Europe, where heat waves this summer have been especially dangerous, proposed several ways of setting your body up for successful thermoregulation.
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If you experience symptoms of heat exhaustion or heat stroke, a fan can be life-saving: “The most efficient and effective way to rapidly reduce body temperature, typically applied in emergency services and the army, is forced ventilation,” the researchers wrote in a paper published Thursday in the Journal of Sleep Research. “[A] fan directed over bare skin, which increases skin humidity loss by facilitating and promoting sweating by convection and evaporation.”
Outside of emergency situations, they continued, a ceiling fan running on low overnight may produce some of the same benefits and help sleepers thermoregulate.
During the day, the researchers recommended exercising early in the morning to maintain a regular circadian rhythm, which could be thrown off by losing sleep. Alcohol dehydrates you and worsens your sleep quality, so the researchers suggested keeping drinking to a minimum and instead hydrating throughout the day.
Aspiring sleepers should take a cool or lukewarm shower, or a lukewarm foot bath, right before bed to reduce heat stress. Don’t layer up, and wear cotton clothing over other materials.
Part of the problem is that falling asleep can be influenced by biological and psychological factors. Worrying about being able to sleep makes it harder to fall asleep, and that’s no different during a heat wave. The researchers recommended using a bed exclusively for sleeping and creating a “reading corner” elsewhere in the home with books, magazines, or comics.
“Use it when you still do not feel sleepy before going to bed, and when you do not manage to return to sleep in the middle of the night. Only go back to bed when you feel sleepy,” they wrote.
The researchers stressed that the use of energy-consuming devices like air conditioners, should “should be seen as a last resort” during heat waves when energy usage might be restricted. Additionally, an AC unit can cool down a room below 63 degrees, at which point sleep can also be disrupted. Opt for an electric fan instead, the authors wrote.
