To support this shift, your body redirects warm blood away from the core and toward the surface—especially the hands and feet. When these areas are exposed to cooler air, they act like natural vents, releasing excess heat and helping your system switch into sleep mode more efficiently.
Perfect heat-release tools
Feet and hands are uniquely suited for temperature regulation because they contain specialized blood vessels known as arteriovenous anastomoses. These vessels allow warm blood to bypass capillaries and move directly to the skin’s surface, making heat loss faster and more effective.
Letting just one foot slip out from under the blanket creates a simple, adjustable cooling mechanism. It’s comparable to opening a window slightly in a warm room—minimal effort, noticeable effect.
“I think it’s likely in service of trying to cool our bodies down because we’ve gotten too warm to sleep,” Natalie Dautovitch, a sleep health researcher and professor at Virginia Commonwealth University, told New York Magazine. “Sticking your toe out or your foot out could bring you to a more restorative sleep.”