- New research found that sleeping in too hot or too cold of an environment could negatively impact someone's quality of sleep.
- The research team found that this lesser sleep quality was more common in environments deemed “too hot.”
- Experts recommend creating a sleep environment that is cool, dark, and quiet for optimal rest.
Yes, there is such a thing as the perfect sleep temperature.
A new study, published in the journal Science of the Total Environment, found that sleeping in a room that’s too hot or too cold can affect the quality of sleep you get.
But, there’s no one-size-fits-all temperature range that most people should set their homes to before going to sleep.
“It varies between different people,” Amir Baniassadi, PhD, a research fellow in medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, and the first author of the new report, told Health.
That said, the new research makes the case for paying attention to the temperature in your home before going to bed, just as you would manage light or noise exposure in order to fall asleep.
“In general, it is recommended that the sleep environment be cool, dark, and quiet,” Andrew Varga, MD, a neuroscientist and physician at The Mount Sinai Integrative Sleep Center and associate professor of medicine at the Icahn School of Medicine at Mount Sinai, told Health.
Here’s how the new research can be applied to your routine, and other tips for getting the best quality sleep.
Getty Images / fizkes
Being 'Too Hot' Is Worse Than Being 'Too Cold'
To understand how temperature impacts sleep quality, the research team collected data from 50 participants, all 65 or older, living in the greater Boston area from October 2021 to February 2023.
Participants’ sleep quality was measured in two different ways: subjectively, using questionnaires, and objectively, using data from a wearable ring device that measures biological signals like heart rate, respiration, skin temperature, movement, and heart rate variability.
The study fills a gap left by previous research because it measured participants’ sleep from their own homes.
“We already know temperature and sleep are related, but most of that [older] research comes from lab-based studies where they bring people into the lab, expose them to different temperatures, see how they slept,” Baniassadi explained.
Data collected from those studies may not translate to real-world circumstances. “We want to know what happens to people inside their homes—that’s the thing that’s new,” he said.
Participants’ home temperatures were typically between 59 and 86 degrees Fahrenheit. While sleep quality declined at either end of the spectrum, it was more pronounced when people’s homes were on the warmer end of the spectrum.
As the temperature increased from 77 to 86 degrees Fahrenheit, sleep quality decreased by up to 10%. This drop is significant enough that it could influence anxiety, mood, cognitive performance, and a person’s stress and activity levels the following day.
That same increase to 86 degrees Fahrenheit was found to affect a person’s sleep similarly to drinking alcohol or consuming nicotine in the evening or living with chronic pain.
It’s well-known that temperature can affect sleep. Varga explained that this could be because our body temperature decreases with sleep.
Previous research has found that sleep is most likely when the core body temperature decreases; it likely won’t occur when that temperature is rising.
The new study noted that an “optimal range” for sleeping is somewhere between 68 and 77 degrees Fahrenheit. But, Baniassadi reiterated that range may not apply to everyone.
If you’re looking to change up your sleep routine, Varga suggests considering trying out a lower temperature first.
“Sleep physicians usually recommend that individuals set a temperature that feels comfortable for them to sleep,” he explained. “That said, if individuals are having issues with difficulty falling asleep initially, we usually recommend erring on the side of keeping the sleep environment cooler.”
The variations in the trend established in the new report warrant further study, Baniassadi said. “We can think about what factors contribute to that—is it biological sex, health status, behavioral [factors]?” he explained. “Just how substantial is the person-to-person variation?”
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Global Warming May Disrupt Sleep Habits
The new findings on how high temperatures affect sleep quality are worrisome to climate researchers, Baniassadi said.
“Most cities in North America are getting warmer,” he explained. “If we know [people’s sleep] will be affected by this, that has public health implications.”
This isn’t the first study to highlight a link between climate change and poor sleep quality. A paper published in the science journal One Earth in 2022 found that by the end of this century, “suboptimal temperatures” could rob us of 50 hours of sleep each year.
People with “lower socioeconomic status” may be most affected by this aspect of global warming; interventions need to be made in order to protect people’s sleep as temperatures rise.
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How to set up your home for better sleep
According to Varga, the temperature of your home is just one of many conditions that influence how well you sleep. “Other main factors include light and sounds, both of which can disrupt sleep,” he explained.
If you’re looking to implement additional changes that may help you sleep better, you can try:
- Installing black-out curtains
- Wearing an eye mask
- Putting tape over (or otherwise covering) light sources, such as blinking lights from electronics
- Wearing earplugs
- Using a white noise machine to block out disruptive sounds
If you try the above modifications and are still having a hard time sleeping, it might be worth consulting a sleep specialist.
The below warning signs, in particular, should prompt a doctor’s visit, Varga said:
- If falling asleep takes longer than 20 minutes
- If you frequently wake during the night and can’t fall back asleep for 20 minutes
- Frequent daytime sleepiness
- Suboptimal cognitive function
Rest is vital to our overall well-being, Varga added, so it’s worth seeking help if you’re dealing with poor sleep quality.
