Perhaps the universe’s most universal truth is that having a single foot sticking out from under the covers is the most comfortable sleeping position. For some reason, curling up completely under the covers is too hot, and throwing the covers off is too cold, but having one foot dangling is perfect. So what exactly is it that makes this feel so right? Sleep expert Terry Cralle says the answer’s in our biology.
“There’s a massive connection between sleep and temperature. In fact, our bodies naturally drop in temperature right before we fall asleep and reach its lowest temperature when we’re in our deepest stage of sleep,” Cralle explains. “That’s why sleep researchers suggest taking a warm bath before hitting the hay—when you get out of the bath, your body temperature will drop, mimicking the natural temperature decrease that occurs before we fall asleep and promoting sleepiness.”
What does that have to do with our feet? A whole lot, actually. “Feet play a huge part in regulating your body temperature because they, unlike other parts of the body, contain arteriovenous anastomoses [links between arteries and veins], which dilate in warm temperatures, allowing more blood to reach the surface of the skin in order to cool it down,” Cralle says. “Plus, the bottoms of your feet are hairless, which helps to keep them cool.” That means, much like Cralle’s warm bath trick, sticking our feet out from under the warmth of the bedding helps along our bodies’ natural pre-sleep cooling process, causing us to fall more quickly into a restful slumber.
In the end, though, Cralle says the only real, scientific evidence we have regarding temperature and how it affects sleep is that people tend to sleep better in rooms that are between 60 and 67 degrees fahrenheit. So if you fear having your bare, uncovered feet snatched by the boogeyman, investing in a fan might be a better alternative than exposing your toes.