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Do You Sleep Better When It's Cold? A Science-Based Answer

by Dale Cudmore | Updated: Aug 31, 2020

Cold is a relative term.

You won’t sleep well if you’re freezing.

But relative to the typical daily room temperature, then yes, most people sleep better at a cold temperature.

I’ll walk you through the research behind this conclusion quickly in this post.

How Cold Temperature Affects Sleep

The main reason temperature is important is that it affects your circadian rhythm.

Everyone has a circadian rhythm, it’s how our body keeps track of what time it is, and when to start preparing for sleep.

As you get closer to bedtime, as lights and temperature in your environment go down, so does your internal body temperature to prepare for your sleep (along with other changes like melatonin production).

Even after going to sleep, your body temperature drops rapidly and remains relatively low until it gradually rises and you wake up (1).

Aside from light, temperature is arguably the most important sleep hygiene factor in getting to sleep, and staying asleep during the night (2).

Have you ever noticed that when you wake up in the middle of the night, it’s usually because you’re too hot?

A relatively high body temperature indicates that it’s time to get up, that’s why it’s harder to sleep when it’s warm (or you have too many blankets).

SummaryIt’s easier to sleep at a colder temperature than you’re used to from the day. Temperature has a big impact on sleep quality, which in turn has effects on your risk of obesity (3), quality of life, and overall mortality (4).

What’s the Ideal Temperature for Sleep?

Okay, so sleeping on the cold side is good, but what specific temperature should you be setting your thermostat at?

It’s a tough question, since every individual is different. It also depends on factors like the number of blankets you have, and heat retention of your mattress.

However, what we can say is that most studies find that an optimal sleeping temperature is between 60-67 degrees Fahrenheit (about 16-19 Celsius) (5).

That’s a recommendation for the majority of people, but some people sleep “hotter” than others. Some sleep experts recommend a range of 65-72 F (18-22 C) (6).

Essentially, it depends on you, so try out a few different temperatures, but that gives you a good range to start with.

Finally, one study in patients with sleep apnea found that patients had better sleep quality at 16 C, but also more symptoms compared to 24 C (7). It’s hard to conclude anything from that, but just be aware that sleep duration may not be the only factor you want to consider (i.e. if it’s too cold, you could be left with a dry throat, leading to other consequences).

SummaryBroadly speaking, most people should try to sleep at a room temperature of 60-72 F (16-22 C). Try a few temperatures out over the course of a few weeks and record your results to see which works best for you.

How Cold Is Too Cold to Sleep In?

While it’s an individual factor, research suggests that sleep quality decreases below 54 degrees Fahrenheit (12 Celsius) (5).

However, some people will have trouble sleeping at temperatures above that, depending on factors like bed warmth.

How Does Sleeping in a Cold Room Affect Your Metabolism?

Some research shows that sleeping in a cold room can cause you to burn more calories.

The most likely explanation is that colder temperatures cause greater activity in brown adipose tissue (“brown fat”), which helps your body consume energy and raise body temperature (8).

A significant increase in brown fat activity can be seen while sleeping at a 19 C temperature compared to 24 C, so you don’t necessarily need to sleep at the coldest temperature possible to see benefits.

Can You Get Sick From Sleeping in a Cold Room?

The cold itself doesn’t make you sick, germs and viruses do, whether you’re outside or sleeping inside.

However, it does appear possible to get sick from sleeping in a cold room in 2 ways.

First, if it’s too cold and you develop low grade frostbite or hypothermia, it will weaken your immune system and can make you more vulnerable to getting sick.

Second, studies have shown that rhinovirus (the common cold) can replicate much easier when your nose is at a cold temperature (9). Considering your nose isn’t covered by blankets usually, sleeping at a cold temperature could make any viruses present more dangerous.

SummaryIt is possible to increase your risk of getting sick from sleeping in a room that’s too cold. However, note that the winter is when many viruses thrive, so it may just be a coincidence if you often get sick in the winter.

How To Make Your Bedroom Colder Without Air Conditioning

I’ve lived in many places where there’s no air conditioning. And even up here in Canada, it still reaches 30+ Celsius in the summer and can be hard to sleep in.

But even if you can’t cool the whole room, you can cool the air around you and keep your body temperature down so that you can sleep better.

Here are your best options:

  • Use a fan - A cheap fan (stationary or rotating) will blow away radiating body heat and keep you a lot cooler. Add a small bucket of ice water in front of the fan to make it even more effective.
  • Sleep with fewer clothes and blankets - In hot weather, you really don’t need any more than a thin sheet. A low thread count (usually cheaper sheets) can be the best choice because the threads are less dense and allow more airflow.
  • Get a gel mattress topper and pillow - If your mattress or pillow seems too hot for comfort, you can add a cooling gel mattress topper or get a pillow designed to be cooler.
  • Stick your feet out - Your body releases heat most efficiently through your extremities (i.e. head, feet). Sticking your feet out of your blankets at the bottom will have a big impact throughout the night.
  • Sleep lower - Hot air rises and cool air falls. In really hot temperatures, I’ve often found sleeping on the ground is most comfortable.

References

  1. The sleep-evoked decrease of body temperature
  2. Body temperature and sleep at different times of day
  3. The association between short sleep duration and obesity in young adults: a 13-year prospective study
  4. Healthy older adults' sleep predicts all-cause mortality at 4 to 19 years of follow-up
  5. Prevention and treatment of sleep disorders through regulation of sleeping habits
  6. Can’t Sleep? Adjust the Temperature
  7. Ambient Temperature and Obstructive Sleep Apnea: Effects on Sleep, Sleep Apnea, and Morning Alertness
  8. Temperature-acclimated brown adipose tissue modulates insulin sensitivity in humans
  9. Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells

Medical Disclaimer: The information on SnoozeUniversity.com is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.


About the authorDale is the founder of Snooze University and a sleep researcher. I overcame my sleep issues and now I'd like to help you do the same by summarizing the latest sleep studies for you.