When you’re right on the cusp of sleep, do you ever resort to the good ol’ foot trick to push you over the edge? You know the one: It’s the move where you slide just one of your feet outside of the covers to feel a bit cooler.
There’s a reason so many of us employ this tactic. Studies have found that our body temperature as well as our bedroom’s ambient temperature play a significant role in the duration and overall quality of our sleep. And leaving one foot uncovered helps us regulate our own body temperature when we’re experiencing that “I’m hot-but-also-cold” conundrum at bedtime.
Sleep Science: Why Cooler Is Better
A sleep study from the National Institutes of Health determined that your bedroom’s temperature is one of the most important factors in sleeping well. A separate investigation from the agency surveyed 765,000 respondents over a nine-year period; this study found that “increases in nighttime temperatures amplify self-reported nights of insufficient sleep.”
Researchers have subsequently determined that a room temperature of approximately 65°F is optimal for high-quality shut-eye, so most of us would benefit by dialing the thermostat back by a few degrees. And if you’re someone who prefers to slumber beneath a pile of blankets, you may wish to adjust the temperature even lower—down to about 61°F.
To understand why our bedroom temperature affects how well we sleep, we need to consider how our body regulates our internal temperature. Over the course of 24 hours, our body temperature naturally spikes and dips, typically peaking in the afternoon and hitting a low at 5 a.m. In order to fall asleep at bedtime, our body temperature cools naturally. Therefore, if we can adjust our thermostat to help facilitate this natural process, we’ll fall asleep faster and more deeply.
Matthew Walker, University of California Berkeley neuroscientist and sleep expert, explained it like this: “Your brain and your body need to drop their core temperature by about two or three degrees Fahrenheit to initiate good sleep. And that's the reason why you'll always find it easier to fall asleep in a room that's too cold than too hot.”
“If our core temperature is too high,” noted Walked, “the brain cannot easily make the switch from being awake to being asleep, or create the best quality sleep."
Tips to Keep the Temperature on Point
There are several simple ways to create a sleeping environment that encourages restorative sleep. To cool things down before bedtime and keep the temperature consistent throughout the night, consider taking the following steps:
- Regulate the Bedroom Temperature: Even if you keep it warmer throughout the day, set your thermostat to 65°F or lower about 30 minutes before bedtime. Smart thermostats make this easy, and they can often program themselves after a few nights. But atmospheric controls are only part of the temperature equation.
- Slow Down to Cool Down: As bedtime nears, limit activities that increase your body temperature. A run before bed is clearly a bad choice, but even chores that require elbow grease, like scrubbing dishes and mopping, should be avoided.
- Lighten Up the Linens: While that big, warm blanket may be comfortable when you first slip into bed, it can cause heat buildup over time. When you shrug it off in the night, you're moving from hot to cold too quickly for comfort, which can disrupt sleep. Using a thicker sheet and thinner blanket allows you to peel back the hottest layer without the shock of cold.
- Upgrade With Modern Bedding: Our bodies produce heat as we sleep—some of us more than others. In order to ensure a consistent temperature throughout the night, you may want to invest in temperature-regulating bedding. Look for sheets, pillowcases, mattress covers and blankets made with fabrics that include heat-dissipating fabrics. These materials feature improved temperature transmission, so they reduce heat concentration throughout the night and help ensure consistent comfort.
After a few nights of employing these tactics to maintain a cooler bedroom and body temperature, you should begin to drift off more quickly and sleep more soundly. Who knows, you may even be able to kick that ole’ foot trick out of bed for good.