Your body sheds heat to fall asleep, and the 60 to 67°F rule is only a rough guide

Key takeaways

• Your core temperature drops as you fall asleep, and warm hands and feet help by letting heat escape, so a cool room and warm toes work as a team³⁴.
• In a study of about 7 million nights in 68 countries, people slept just over 14 minutes less on nights above 86°F, and older adults, women and people in lower-income countries lost the most¹.
• The popular 60–67°F range is a sensible starting point, not a tested sweet spot; in one in-home study, older adults slept best between 68 and 77°F²⁷⁸.
• Cooling mattresses and toppers have helped in small lab trials, most clearly on hot nights, but the research is thin, and two of the three studies we found were paid for by the makers⁶¹¹¹².
• During a heat wave, don’t rely on a fan: CDC advises air conditioning, cool showers and visits at least twice a day to older adults in your care¹³.

In 2022, researchers led by Kelton Minor of the University of Copenhagen published a study built on about 7 million nights of sleep. The data came from wristband trackers worn by more than 47,000 adults in 68 countries¹.

On nights above 86°F, people slept just over 14 minutes less on average¹. Most of the loss came at the edges of the night. People fell asleep later and woke up earlier¹.

That sounds small. But the team projected that by 2099, too-warm temperatures could cost each person 50 to 58 hours of sleep a year, depending on the world’s greenhouse gas choices¹. Older adults, women and people in lower-income countries lost the most¹.

So how cool should your bedroom be? The usual answer is 60 to 67°F, and Cleveland Clinic sleep specialist Dr. Brian Chen repeated it in May 2026 as a range that is often recommended².

That range is a fair place to start. But no study we found tested it against other ranges, and some people, especially older adults, may sleep better a few degrees warmer.

We walk through how your body uses temperature to fall asleep, what heat does to a night, and how to cool a bedroom with or without air conditioning.

Falling asleep is a heat-dumping job

Your core temperature, the heat deep in your chest and belly, rises and falls on a daily rhythm. Most mammals, people included, sleep near the low point of that curve⁴.

A 2007 review in Sleep Medicine Reviews described the timing. Sleep usually begins as core temperature heads downhill, when the body is shedding heat fastest⁴.

The exit route is your skin, especially your hands and feet. Blood vessels there widen before bed, sending warm blood to the surface, where the heat can leave⁴.

In 1999, Kräuchi and colleagues reported in the journal Nature that this widening in the hands and feet was the best body signal for predicting how fast people fell asleep³. Their title said it plainly: “Warm feet promote the rapid onset of sleep”³.

The reverse also seems to hold. Women whose hands and feet tend to stay cold took longer to fall asleep, the 2007 review noted⁴.

That explains a setup that sounds like a contradiction: cool air and warm extremities. The room pulls heat away, and warm hands and feet let it go.

Under the covers, you build a climate of your own. Normal sleep happens when the air between your skin and the bedding sits around 90 to 93°F, at 40 to 60% humidity, according to a 2012 review in the Journal of Physiological Anthropology⁵.

Heat steals deep sleep and dream sleep

That 2012 review ranked the thermal environment among the biggest influences on human sleep⁵. For people sleeping with normal bedding and clothes, heat disrupted sleep stages more than cold did⁵.

In the lab studies it summarized, heat exposure⁵:

• increased time spent awake;
• cut REM sleep, the stage tied to vivid dreams;
• cut slow-wave sleep, the deepest stage.

The damage clustered early in the night. People also didn’t get used to it: sleep stayed disturbed after five straight days of heat⁵.

Humidity makes things worse. Humid heat added more waking, took more deep and REM sleep, and blunted the normal nighttime drop in core temperature⁵.

A 2026 trial in the Journal of Sleep Research put a number on one hot night. In a randomized, double-blind design, 15 healthy, active young adults slept in a lab at about 72°F and at about 90°F⁶.

The hot night cut about 25 minutes of sleep. It also reduced REM sleep and sleep efficiency, the share of time in bed spent asleep, and it added time awake⁶.

Outside the lab, the wristband study saw the same pattern in people’s own beds¹. It had no data on who had air conditioning, so it couldn’t say how much AC protects¹.

Where the 60–67°F rule comes from

You’ll see 60 to 67°F (about 15 to 19°C) almost everywhere. Cleveland Clinic sleep psychologist Michelle Drerup gave that range in 2021 and described the ideal bedroom as cool, dark and quiet⁷.

Her article cited one study: the 2012 review⁷. The 2026 Cleveland Clinic piece cited none².

The review itself doesn’t name 60 to 67°F as the best range. What it shows is that, with bedding and clothes on, cool rooms didn’t disrupt sleep stages in the studies it covered, though cold still changed how the heart was regulated during sleep⁵.

So the popular range falls in cool territory where, with decent covers, sleep stages tend to hold up. It works as a rule of thumb. It isn’t a measured sweet spot, and it says nothing about humidity, bedding or age.

Take away the covers and the picture flips. For people sleeping nearly nude and uncovered, the neutral room temperature was about 84°F, and rooms colder than that disturbed sleep more than warmer ones did⁵. Your blankets matter as much as your thermostat.

Older sleepers may do best a few degrees warmer

In 2023, researchers at Hebrew SeniorLife’s Hinda and Arthur Marcus Institute for Aging Research and Harvard Medical School tracked 50 older adults in their own homes, according to a release from Hebrew SeniorLife about the study in the journal Science of the Total Environment⁸. Wearable sleep monitors and bedroom sensors logged nearly 11,000 nights⁸.

Sleep was at its most efficient and restful when the bedroom stayed between 68 and 77°F (20 to 25°C)⁸. Warmer than that, efficiency slipped: by 5 to 10% between 77 and 86°F, which the study’s abstract calls clinically relevant⁸.

The bigger lesson may be how much people differed. Each person’s best temperature varied a good deal from the next person’s⁸. The study was observational, so it shows a pattern. It doesn’t prove that changing the thermostat changes sleep.

Aging bodies also handle heat differently. In older adults, even mild heat increased waking and cut REM sleep, the 2012 review found⁵.

The practical takeaway: an older person shouldn’t shiver under the covers to hit 62°F. Starting near 68°F and adjusting by how they sleep fits the evidence better.

Bed socks are an old habit with a small study behind it

Warming your feet before bed is a common winter habit, and bed socks are popular in Korea, researchers Ko and Lee noted in a 2018 paper⁹. They decided to test it.

Six young men slept for seven hours in a 73°F room, which the researchers called cool, once with bed socks and once without⁹. With socks, the men fell asleep 7.5 minutes faster, slept 32 minutes longer and woke up less often⁹. Their feet ran 1.3°C (about 2.3°F) warmer, but their core temperature didn’t change⁹.

Six people is a tiny sample, and other warming tricks show mixed results. In a 2020 randomized trial in Scientific Reports, a warming eye mask helped 18 men fall asleep faster than a look-alike sham mask, and it warmed their hands and feet¹⁰. Kao Corporation funded that study, and one author worked for the company¹⁰.

The same paper pointed to earlier studies that found no significant change in how fast people fell asleep, including one that tested a warm footbath in older adults with sleep problems¹⁰.

This is where natural-health instincts and sleep science meet. Your body already runs its own sleep aid: a nightly cooling cycle that works through your skin. A cool room, a light blanket and a pair of socks support that system instead of overriding it, and they cost little or nothing.

Tradition got here first, and the early science partly agrees. That’s a good reason to try socks, not proof they’ll work for you, so judge them by how you sleep.

Warm baths use the same heat-dumping system. Our article on evening routines covers bath timing.

Cooling mattresses and toppers: real physics, company money

Some cooling products do something measurable. In a 2018 single-blind trial in Physiology & Behavior, 15 healthy young men slept on two mattresses in random order in a room kept near 73°F¹¹. One had a dense top layer designed to soak up body heat. The other was plain foam¹¹.

On the heat-absorbing mattress, average core temperature ran about 0.16°C lower over eight hours. Deep sleep rose from 23.1% to 26.8% of total sleep¹¹. Technogel Italia, which makes the heat-absorbing layer, funded the work through an unconditional grant to the University of Torino¹¹.

The 2026 heat study tested a topper built to carry heat away from the body⁶. At about 90°F, it gave back about 21 of the minutes the heat had taken, with more REM sleep and better efficiency⁶. At about 72°F, it didn’t add total sleep⁶. The study record we read didn’t list a funder.

Then there’s the newest wave: app-controlled pads that circulate cooled water under you. A September 2026 preprint, a paper not yet reviewed by outside scientists, tested one such topper in 14 owners at home¹².

Everyone got a sham week first and an active week second, so the order wasn’t random¹². People said they slept better and felt sharper. Yet their Oura rings showed no significant change in time to fall asleep, time awake, sleep efficiency or total sleep¹². The device’s maker paid for the study, and both authors work for the company and own equity in it¹².

The pattern: cooling gear helps most when your room is hot. In a comfortable room, the measured gains are smaller, such as a bit more deep sleep⁶¹¹. Ask who funded the study before you spend.

What the evidence supports

Claim	Evidence level	What the research shows
A hot bedroom disturbs sleep	Strong evidence	Lab studies show more waking and less deep and REM sleep; 7 million real-world nights show shorter sleep on hot nights156
Humid heat is worse than dry heat	Promising but early	Consistent lab findings, mostly in small groups5
60–67°F is the best range for everyone	Not enough evidence	Widely repeated; no head-to-head test of ranges found257
Older adults sleep best around 68–77°F	Promising but early	One observational study of 50 people; big person-to-person differences8
Warm feet help you fall asleep faster	Promising but early	Strong physiology; small trials with mixed results3910
Heat-absorbing or cooling mattresses help on hot nights	Promising but early	One small lab trial on a hot night; a second, maker-funded trial found smaller gains in a comfortable room611
App-controlled cooling pads improve measured sleep	Not enough evidence	Company-run preprint; wearable measures didn’t change12
A fan alone keeps you safe in extreme heat	Evidence says no, or unsafe	CDC advises against relying on a fan as your main cooling13

A cool-bedroom checklist, with or without AC

Start with a simple room thermometer by the bed. Then test, because your best number may differ from anyone else’s⁸.

If you have air conditioning

• Treat 60–67°F as a starting point, or start near 68°F for an older sleeper⁷⁸.
• Change one thing at a time, by 2 degrees, and hold it for a week.
• Cool the room before bed, so you aren’t lying in the warmest air of the night.
• If the room feels muggy, run a dehumidifier. Humid heat is harder on sleep than dry heat⁵.
• Keep a light blanket and socks nearby, so the room can stay cool while your feet stay warm⁹.

If you don’t have air conditioning

• Skip the stove and oven on hot days; they heat the house¹³.
• Take a cool shower or bath before bed¹³.
• Wear loose, lightweight clothing to bed¹³.
• Close blinds on sunny windows during the day, and open windows when the outside air is cooler than inside.
• Use a fan for comfort on warm nights, but don’t count on it when it’s very hot¹³.
• On dangerous nights, ask your local health department about an air-conditioned shelter¹³.

Heat is a health risk, not only a sleep problem

Older adults face more danger in a hot bedroom. According to CDC, an older body copes less well when the temperature jumps quickly. Long-term health problems can change how it responds to heat, and some common prescriptions interfere with sweating or with holding a steady body temperature¹³.

On dangerous days, CDC’s advice is to spend as much time as you can in air-conditioned places¹³. If you look after an older relative or neighbor, visit them at least twice a day, and type your ZIP code into CDC’s HeatRisk dashboard for a local forecast¹³. On a fluid limit or a diuretic (“water pill”)? Ask your doctor for a hot-weather drinking target¹³.

Cramping muscles, a headache, nausea or vomiting in the heat can signal heat-related illness and need prompt medical care¹³. Call 911 in an emergency.

Some night heat comes from inside. If hot flashes or night sweats wake you, our upcoming article on menopause and sleep covers options.

See a clinician if a cooler room doesn’t help and you notice any of these:

• loud, frequent snoring with pauses in breathing, gasping or choking¹⁴;
• trouble sleeping at least three nights a week for three months or more¹⁵;
• regularly taking more than 30 minutes to fall asleep, or feeling sleepy during the day¹⁴;
• prickling or tingling in your legs in the evening or at bedtime that eases when you move¹⁴;
• acting out your dreams¹⁴.

If you feel drowsy behind the wheel, pull over¹⁴. Our upcoming articles on sleep disorders cover each of these in depth.

Questions readers ask

The bottom line

Your body falls asleep by shedding heat, and warm hands and feet are part of how it does that. Heat and humidity cut deep sleep, dream sleep and total sleep, and the effect shows up from sleep labs to millions of real nights.

Treat 60–67°F as a starting point, not a law. Older sleepers may do better near 68–77°F, and everyone differs, so let a thermometer and your own nights decide. Socks and good bedding cost little. Cooling gear helps most on hot nights, and in a heat wave, real cooling and check-ins on vulnerable people matter more than any gadget.

Related reading

• Sleep trackers count your hours well, but their sleep stages are rough guesses
• Who paid for the study matters, even when the science is real
• Sleep, food and easy days beat most recovery gadgets
• Six questions to ask before you buy anything for your health
• How a night of sleep unfolds, from deep sleep first to dreams last

Sources

1. Minor K, Bjerre-Nielsen A, Jonasdottir SS, Lehmann S, Obradovich N. “Rising Temperatures Erode Human Sleep Globally.” One Earth, 2022;5(5) (Cell Press release via ScienceDaily, May 20, 2022). sciencedaily.com
2. Cleveland Clinic. “Best Bedroom Temperature for Sleep.” Cleveland Clinic Newsroom, May 14, 2026. newsroom.clevelandclinic.org
3. Kräuchi K, Cajochen C, Werth E, Wirz-Justice A. “Warm Feet Promote the Rapid Onset of Sleep.” Nature, 1999;401(6748):36–37 (IDEAS/RePEc record). ideas.repec.org
4. Kräuchi K. “The Thermophysiological Cascade Leading to Sleep Initiation in Relation to Phase of Entrainment.” Sleep Medicine Reviews, 2007;11(6):439–451 (EM-Consulte abstract). em-consulte.com
5. Okamoto-Mizuno K, Mizuno K. “Effects of Thermal Environment on Sleep and Circadian Rhythm.” Journal of Physiological Anthropology, 2012;31:14. jphysiolanthropol.biomedcentral.com
6. Pasquier F, Monin J, Tardo-Dino P-E, et al. “Protective Effect of a High Heat Conductivity Mattress Topper on Sleep During Heat Night.” Journal of Sleep Research, 2026. DOI 10.1111/jsr.70137 (PubMed record mirror). guidelinecentral.com
7. Cleveland Clinic. “What’s the Ideal Sleeping Temperature for My Bedroom?” Cleveland Clinic Health Essentials, November 16, 2021. health.clevelandclinic.org
8. Hebrew SeniorLife Hinda and Arthur Marcus Institute for Aging Research. News release on Baniassadi A, Manor B, Yu W, Travison T, Lipsitz L, “Nighttime Ambient Temperature and Sleep in Community-Dwelling Older Adults,” Science of the Total Environment, 2023 (DOI 10.1016/j.scitotenv.2023.165623), as posted by Neuroscience News, August 28, 2023. neurosciencenews.com
9. Ko Y, Lee J-Y. “Effects of Feet Warming Using Bed Socks on Sleep Quality and Thermoregulatory Responses in a Cool Environment.” Journal of Physiological Anthropology, 2018;37:13 (DOAJ record). pubmed.ncbi.nlm.nih.gov
10. Ichiba T, Suzuki M, Aritake-Okada S, Uchiyama M. “Periocular Skin Warming Promotes Body Heat Loss and Sleep Onset: A Randomized Placebo-Controlled Study.” Scientific Reports, 2020;10:20325. link.springer.com
11. Kräuchi K, Fattori E, Giordano A, et al. “Sleep on a High Heat Capacity Mattress Increases Conductive Body Heat Loss and Slow Wave Sleep.” Physiology & Behavior, 2018;185:23–30. DOI 10.1016/j.physbeh.2017.12.014. doi.org
12. Tucker L, Zwiebel J. “In a Sham-Controlled At-Home Study, Sleeping on a Temperature-Controlled Mattress Topper Improved Sleep Quality, Mood, and Mental Acuity.” Research Square (preprint, not peer reviewed), September 16, 2026. researchsquare.com
13. Centers for Disease Control and Prevention. “Heat and Older Adults (Aged 65+).” CDC, last reviewed June 25, 2024. cdc.gov
14. National Heart, Lung, and Blood Institute. “Your Guide to Healthy Sleep.” NIH Publication No. 11-5271, revised August 2011. nhlbi.nih.gov
15. National Heart, Lung, and Blood Institute. “Insomnia: Diagnosis.” NIH, updated March 24, 2022. nhlbi.nih.gov