Each and every one of us has a favourite sleeping position—whether it’s the fetal curl, the splaying starfish, the yearner’s stretch, or the log pose. But there’s one sleep habit we all have in common, and that’s our tendency to sleep under a blanket.
Although bedding used to be a luxury reserved for the rich and powerful, such as kings and wealthy merchants, these days sleeping under a blanket is fairly universal. And even if you’re roasting in your airless room, chances are you’ll still get tucked in. What gives?
As always, science saves the day with the answers to our deepest questions. For one, your body’s core temperature drops before and during your slumber, so you need the blanket to stop your shivers. That nightly cool down begins about an hour before you hit the hay and continues to drop while you sleep, eventually reaching one or two degrees below your average body temperature. But once you reach the rapid eye movement (REM) sleep cycle, your body loses its ability to regulate its temperature. Your blanket is around to keep you warm—even on a sweltering summer evening.
There’s a behavioural element to sleeping with bedding, too. Truth be told, we’ve been conditioned to use blankets since birth.
“Chances are you were raised to always have a blanket on you when you went to sleep,” Dr. Alice Hoagland, the director of the insomnia clinic at the Unity Sleep Disorder Center in Rochester, New York, told Atlas Obscura. “So that’s a version of a transitional object, in sort of Pavlovian way.”
Previous research also suggests that sleeping with a weighted blanket can do wonders for patients with anxiety and insomnia. Why? Sleeping underneath your bedding makes you feel safe and protected, which increases your brain’s serotonin levels and decreases the presence of stress hormones.
Scientific explanations aside, blankets are just plain soft and comfy. That’s reason enough to get tucked in tonight.
Originally published as There’s a Scientific Reason Why You Always Sleep Under Blankets—Even When It’s Hot on ReadersDigest.com.