Ever wonder why so many people stick one foot out of the blanket to fall asleep? Science has an answer.

According to María José Martínez of the Spanish Sleep Society, the body needs to cool down in order to rest. This happens through vasodilation—blood vessels open in the skin, hands, and feet to release internal heat. Sticking a foot out helps speed up this process, lowering body temperature so sleep comes more easily. Babies show this clearly, as their ears and noses warm up before dozing off.

To sleep better, experts recommend keeping a consistent schedule, eating light at night, creating a cool and dark environment, limiting naps, exercising regularly, and managing worries before bed.