Having cold feet is a hassle in many situations—especially when you’re heading to bed.

“Our body temperature guides our sleep cycle,” says Kenneth Diller, a professor of biomedical engineering at the University of Texas at Austin who has . “Your body works best when the core area is cooler and the extremities are warmer.”

Research indicates that people with warm hands and feet fall asleep faster than those with cold extremities. Here’s why—plus the top ways to put this into practice.

The scientific reasoning behind it

When you’re getting ready for sleep, your body needs to cool down to signal it’s time to rest. Interestingly, warming your hands and feet helps this happen because your body uses these areas as heat-release zones, Diller explains. When your extremities are warm, blood flows more smoothly to the skin, allowing excess heat from your core to escape. As your core temperature drops, your brain gets the message that it’s time to drift off. If your hands and feet stay cold, though, that heat can’t escape as well—making it harder to fall asleep.

Warming your hands and feet “effectively leads your body into sleep,” Diller says. Otherwise, “you just lie there feeling uncomfortable.”

Top warming techniques

Years ago, Diller’s wife made a rule. “In our family, there was an absolute rule: when my hands and feet are as cold as icicles, there’s a virtual wall between the two sides of our bed,” he says. Luckily, there are many ways to warm your hands and feet before bed.

One obvious method: taking a . Diller usually works out in the evening then jumps into the shower. At the end, he “turns the temperature up to a point that’s initially a bit painful but you get used to it,” he says. (Do not exceed 111°F, which he notes is the .) “One night while showering, I looked down at my hands and they were red,” he says—this meant blood was flowing to the AVAs, or specialized blood vessels in the hands and feet that open wide to release heat. “I thought to myself: ‘I might have made a great discovery.’”

Diller also likes heating pads. One night, while testing which warming techniques worked best, he put one under his pillow. When he and his wife went to bed, they read for a while as he warmed the area over his cervical spine (which helps control body temperature). “It’s like holding a match under the thermostat—it changes how your body regulates heat,” he says. “Amazingly, my hands and feet got toasty warm in just a few minutes.”

Of course, if you don’t want to overcomplicate your bedtime routine, you can just put on your favorite fuzzy socks. No matter the method, the goal is to remove one of the biggest barriers to sleep. Cold hands and feet keep the nervous system alert; warmth helps it calm down.

“As long as my hands and feet are cold,” Diller says, “I won’t be able to fall asleep well.”