Do you sleep with the heat cranked up high, cuddled under layers of blankets? Or do you keep your window open in dead of winter to keep your room chilly? During the day, I tend to run on the cold side, constantly wearing layers to stay warm. But at night, I can’t stand being too warm and almost always like to have fresh, cool air coming in through a cracked window. We all have unique preferences for our sleeping environment, but if you are a poor sleeper, adjusting some of your habits might help you out. Research shows that while the best temperature for sleep can vary between individuals, keeping your room colder, rather than warmer, will help you to sleep better.

Why temperature matters for sleep

Regulation of body temperature is tightly associated with the sleep-wake cycle, as both are regulated by the circadian rhythm, our biological 24-hour clock. Because of this, the core body temperature naturally decreases during sleep. And sleep is most likely to occur when the core body temperature decreases, and it least likely when the temperature is increasing.[1] This is why we can sleep easier when the room temperature is lower than we might prefer during the day.

Cooler temperatures more conducive to better sleep

People tend to sleep better in a cool environment rather than a warmer one. For example, one study of over 600 adults found that higher temperatures in summer were associated with increased fatigue scores. This was especially true for poor sleepers, who were affected by increased air temperature much more than good sleepers.[2] Elderly people can be particularly influenced by even mild heat exposure, which can cause increased wakefulness and decreased REM sleep.[1]

Heat exposure can actually affect slow wave sleep and REM sleep, while cold does not have these effects. High humidity is also associated with poorer sleep.[1]

The best temperature for sleep is probably between 60 and 67°F (while wearing pajamas and using at least one cover), which is probably colder than you keep your home during the day. Sleeping in a much warmer room, as well as one that is too cold, will probably keep you up and disrupt a good night’s rest.[3] If you are used to sleeping much warmer than this, making incremental changes in your room temperature can help you to get used to the cooler temperature.

Sleep cooler, stay healthier?

Lowering your thermostat might also keep your body healthier. A very small study provides compelling results suggesting that the temperature at which we sleep can impact our metabolism of fats. Men who slept at 66°F for one month had a 42% increase in brown fat volume and a 10% increase in fat metabolic activity. Brown fat, as opposed to white fat, is the good kind of fat, which can help you to lose weight and protects against insulin resistance. Once the men went back to sleeping in warmer temperatures, these changes were reversed. The authors conclude that humans might be able to acclimate to sleeping in colder temperatures, which could lead to healthier glucose and fat metabolism.[4]

Other tips for getting a better night’s sleep include removing cell phones from the bedroom, avoiding blue light exposure at night, and taking natural, sleep promoting supplements.

Share your experience

What temperature do you prefer for sleep? What healthy sleep habits do you practice? Share your experience in the comments section below.

[1] J Physiol Anthropol. 2012 May 31;31:14.

[2] Environ Res. 2015 Feb 12;138C:17-21.

[3] Presse Med. 1994 Mar 12;23(10):485-9.

[4] Diabetes. 2014 Nov;63(11):3686-98.