Many people have unique bedtime habits: a favorite pillow, a firm mattress, or complete darkness. Yet one common habit stands out—sticking a foot out of the sheets. Surprisingly, science explains why this simple action can improve sleep and overall health.

The Science Behind the Habit
This nightly habit relates to regulating body temperature. María José Martínez, coordinator of the Chronobiology group at the Spanish Sleep Society (SES), explains:

“To sleep, our body must expel internal heat through vasodilation.”

Think of the human body as a machine. After a long day, it overheats and needs to “air out” to rest properly. Vasodilation opens the blood capillaries in peripheral areas like the hands and feet, increasing skin temperature and releasing excess heat.