You’ve probably done it without thinking—kicking one foot out from under the blanket to cool down at night. While it may feel like a simple comfort habit, science suggests it can actually help your body fall asleep faster. As bedtime approaches, your body naturally prepares for sleep by lowering its core temperature. This cooling process is a key part of your circadian rhythm and helps trigger the release of melatonin, the hormone that promotes sleep. To speed this up, your body sends warm blood away from the core and toward the skin—especially the hands and feet.

Feet are particularly effective at releasing heat because they contain special blood vessels that allow warmth to escape quickly. When one foot is exposed to cooler air, it acts like a natural heat vent, helping your body cool down more efficiently without drastic measures like removing blankets or lowering the thermostat.

Sleep researchers also measure something called the distal-to-proximal gradient (DPG), which compares the temperature of your extremities to your core. A higher DPG—meaning warmer hands and feet relative to the body—has been linked to faster sleep onset. Studies show that people who release heat through their feet tend to fall asleep more quickly. That said, the trick doesn’t work for everyone.

People with cold feet, poor circulation, or certain conditions may find it uncomfortable and sleep better by keeping their feet warm instead. Ultimately, the goal is comfort. But if you’re struggling to drift off, slipping one foot out from under the covers might be a surprisingly effective way to help your body settle into sleep naturally.