Why People Stick a Foot Out from Under the Sheets While Sleeping
Many of us have bedtime rituals: a favorite pillow, a firm mattress, or total darkness. But one curious habit often goes unnoticed—sticking a foot out from under the sheets. Surprisingly, science shows that this simple action can help improve sleep quality and even benefit overall health.
The Science Behind the Habit
This habit is all about regulating body temperature. María José Martínez, coordinator of the Chronobiology group at the Spanish Sleep Society (SES), explains:
“To sleep, our body must release internal heat through vasodilation.”
After a long day, our bodies can overheat and need to “cool down” to rest properly. Vasodilation—the widening of blood vessels in peripheral areas like the hands and feet—helps release excess heat and raise skin temperature in these areas.
That instinct to stick a foot out of the sheets? It’s your body naturally cooling itself, preparing for deep, restorative sleep.
Martínez adds that this is easy to see in babies:
“When they’re sleepy, their ears and nose turn red and warm. They are vasodilating to release heat and fall asleep.”
In short, exposing a foot (or other extremities) lowers your internal temperature, signaling your body that it’s time to sleep.