It’s a common conflict among bed partners: One person wants the bedroom to be almost tropical, so they can sprawl out on top of the covers, wearing little to nothing; the other likes it on the colder side so they can snuggle up under the duvet. Besides leading to ongoing battles over control of the thermostat, these disparate desires beg the question: Is there an ideal temperature for sleep?
The answer is: Yes! But it’s more of a temperature zone than a specific number. Many sleep researchers say that between 60 and 67 degrees Fahrenheit (15.5 and 19.4 degrees Celsius) is the ideal temperature for sleep.
However, Dr. Chris Winter, a neurologist and sleep specialist in Charlottesville, Virginia, favors a narrower range. “Somewhere between 65 and 67 yields the most sleep continuity, efficiency [the ratio between how much time someone spends asleep to how much time the person spends in bed], and depth of sleep,” he says. “Humans tend to sleep better in cooler temperatures, whereas heat is disruptive to sleep. It leads to more awakenings.”
From falling asleep to staying asleep and spending enough time in the various stages of sleep for restoration, read on to learn how big of a role heat and cold play when it comes to your sleep quality.
Why temperature can affect the quality of your sleep
One of the most common tips for good sleep hygiene is: Keep your bedroom dark, quiet, and cool. However, in addition to ambient temperature, there’s another factor that controls sleep regulation: your body temperature.
1. Temperature drops tell your body it’s time to sleep
Your body’s circadian rhythms — the internal, biological processes that regulate the sleep-wake cycle, body temperature, and many other essential functions — reach their daily peak between 4 and 6 p.m. and start dropping around bedtime. Your body temperature is included in these drops.
This body temperature drop is a natural trigger for sleep, Winter explains. “Sleep is controlled in the brain stem and the hypothalamus, which regulates body temperature,” he says. Once your body temperature goes down, it remains low while you sleep, then rises again one to two hours before you wake up.
2. High temperatures can make it harder to fall asleep
Research has found, however, that ambient room temperature may disrupt your sleep by affecting your body’s ability to regulate its internal temperature.
In particular, sleeping in a warm room can prevent your body from lowering its internal thermostat appropriately during the night, which would help facilitate uninterrupted sleep. This can make it harder to fall asleep or stay asleep throughout the night.
3. Extreme temperatures can wake you up at night
Ambient temperature extremes also increase spontaneous arousals, Winter says. After a night spent tossing and turning in a pool of sweat or after hours of trying to burrow beneath the covers to get warm, it’s no wonder you feel tired in the morning.
Even if you don’t remember trying to get comfortable at night, it’s possible to have experienced disrupted sleep due to temperature shifts. “Some of [the awakenings] you might be conscious of, and some of which you might not,” Winter confirms.
4. High temperatures can reduce deep and REM sleep quality
What’s more, ambient temperature extremes that leave you shivering or sweating lessen deep sleep and REM sleep, Winter says.
Interestingly, research has found that the body’s ability to regulate its temperature is suspended during REM sleep for reasons that aren’t understood. But decreases in REM sleep due to ambient temperature being too high or too low can lead to more fragmented sleep and leave you feeling unrestored in the morning.
This is another reason why it’s important to have your sleeping environment in the optimal temperature zone — to take the pressure off your body to regulate its own temperature.
The ideal sleep temperature for infants and children
While some experts advise keeping a baby’s room temperature between 68° and 72°F (20 to 22°C), Winter believes this recommendation is based more in theory than scientific evidence. But it is true that babies don’t have the same ability to regulate their body temperature as adults do, Winter notes.
And since it isn’t safe for them to sleep with covers or a blanket because of risks of suffocation — and blankets could cause overheating, which increases risk of Sudden Infant Death Syndrome (SIDS) — it’s important is to follow the Goldilocks principle and stick with an ambient temperature for your baby’s room that’s neither too hot nor too cold.
“As kids grow, their metabolisms are strong and they generate a lot of heat,” says Winter, author of “The Rested Child.” Older children and teens may benefit from sleeping with lighter bedclothes and bed coverings that they can add on or take off on an as-needed basis.
The ideal sleep temperature for older adults and seniors
When it comes to adulthood, hormonal fluctuations during menopause often cause hot flashes and night sweats, which can severely disrupt a woman’s quality of sleep. It may help for women going through the menopausal transition to sleep in a slightly cooler room and to wear pajamas that are made with moisture-wicking fabrics; placing a fan nearby or using a cool bedding or a cooling pillow can also make a difference, Winter says.
Keeping the bedroom cool can also help people with obstructive sleep apnea, which becomes more common as people get older. In fact, a 2021 study found that when adults with sleep apnea slept in an environment where the temperature was 60°F (16°C), they slept longer, had higher sleep efficiency, and felt significantly more alert in the morning when they compared to when they snoozed in a setting where the temp was 75°F (24°C).
Temperature tips for regaining snooze control
Rest assured (pun intended): “Sleeping in the wrong temperature won’t make you sick,” Winter says. But it may put you at risk for poorer sleep, which can compromise the way you feel and function throughout the day.
In general, he says, it’s better to skew on the colder side than the warmer one in the bedroom because cold reduces inflammation in the body, which is beneficial to your overall health.
“If 65 degrees is too cold for you, try setting the thermostat to 69 degrees for a week then dropping it by a degree,” Dr. Winter advises. “You have to do the experiment yourself.”
Some other strategies that may help enhance your sleep environment throughout the seasons:
If your room is too cold:
While it’s generally easier to fall asleep while it’s chilly, it’s possible for ambient temperature to get too cold, especially when you are sleeping in different locations, like a home without proper insulation or a tent.
- Place an extra blanket (or two) on the bed that you can pull on or off as needed.
- Put socks on your feet. A 2018 study found that wearing socks to bed in a cool environment reduces the onset of sleep and sleep awakenings and increases total sleep time and sleep efficiency. The theory is that warming the feet this way might activate the thermosensitive neurons in areas of the brain that regulate sleep.
- Hug a warm compress or water bottle to sleep. Or place it at the foot of your bed, so that it can work in a similar way to wearing socks. Wrap the bottle or compress in a towel if it is too hot initially.
- Take a warm bath or shower before turning in. Research shows that it helps people fall asleep faster and improves sleep efficiency). The reason: After your body temperature is elevated by exposure to the warm water, it drops a short while later, which sets the stage for sleep.
If your room is too hot:
Hot sleep is also a tricky situation to navigate, as there are many causes, from hot flashes to heat waves, but it’s not impossible with a little planning ahead.
- Use a fan to keep the air circulating. Research shows that improving air flow reduces awakening during sleep in warm weather.
- Wear lightweight pajamas — or sleep naked — to optimize your body’s ability to cool itself.
- Invest in cooling bed technology — mattress pads, pillows, sheets, and more — for your bedroom. A 2003 study found that using a cooling pillow during sleep decreases the body’s sweat rate under humid heat conditions. The same effects can occur with other cooling technology for the bed.
- Open the window. Fresh air can help ventilate the room and help maintain your ideal ambient temperatures when if you don’t have an AC unit.
Of all the sleep hygiene tips, regulating ambient temperature — or your body temperature — goes a long way with facilitating better sleep. If you are looking for the most effective way to improve your sleep quality, try making sure the temperature of your room is just right.
