It’s often said that keeping your bedroom at precisely 68°F is the surest way to achieve the most restful sleep possible. But how true is it that there is an ideal temperature for sleeping? We’ll tell you how that conventional wisdom may not be totally accurate, how temperature and sleep quality are related, and how you can get that perfect sleep temperature profile right for you.
"Much like your sleep pattern, your body temperature also follows a 24-hour cycle as part of the circadian rhythm. Generally speaking, your body temperature decreases at night and rises during the day."
Is 68° the most ideal temperature for sleeping?
Let’s get this out of the way. No, there is no one optimal temperature that will give everyone the best sleep throughout the night. Moreover, your body temperature changes throughout your sleep, and your temperature needs change along with it.
Much like your sleep pattern, your body temperature also follows a 24-hour cycle as part of the circadian rhythm. Generally speaking, your body temperature decreases at night and rises during the day (within 2-3°F normally).
To cool off, your body will slow down its metabolism to generate less heat and increase blood flow to your extremities and skin. Higher blood flow in the limbs and skin allows heat from your body’s core to dissipate into the environment quicker. That’s why you may actually feel warmer as you get tired at night as the blood vessels in your skin let more heat to the surface (where your temperature-sensing nerves are), even though your body overall is cooling down.
A study from 1981 demonstrated that sleep typically starts while the body is cooling off, shortly before it hits the minimum temperature for the day. These researchers found that the duration of sleep heavily depends on the time difference between falling asleep and when the body reaches its minimum temperature. The earlier you fall asleep before you hit minimum temperature, the longer you sleep.
Not only does the duration of sleep rely on body temperature, but the type of sleep does also. Rapid eye movement, or REM, is a deep stage of sleep important for learning and maintaining high-level thought. REM sleep starts shortly after the body reaches its coolest point, on the upswing back to a warmer temperature.
With sleep timing and progression linked so closely with body temperature, maintaining a proper body temperature is an important step in ensuring a healthy sleep pattern.
How does bedroom temperature affect me during sleep?
Being too hot or too cold has serious impacts on the quality of sleep a person gets. Researchers have found that either being too cold or hot reduces the amount of time a person spends in REM sleep and increases the amount of time a person spends in less-restful sleep stages.
During REM sleep, the body is actually less effective at maintaining the right internal temperature. Theories suggest that there is overlap between the brain circuits that respond to external heat cues and the circuits that initiate or suppress REM sleep, so that REM sleep brain signals temporarily override the temperature-regulating signals. This may explain why being outside a comfortable temperature range causes poorer sleep. The body normally increases metabolism to generate more heat in case it gets too cold, or increases the amount of sweat in case of too much heat. In the REM stage, however, it doesn’t do either of these. The body just isn’t as good at maintaining optimal temperatures during sleep, so help from your sleep system– bedding, clothing, and sleep surface– is important in keeping the temperature just right.
Of course, there are products available to help regulate your sleeping temperature through the night, such as programmable thermostats or heating blankets. However, these solutions don’t track your sleep patterns to respond to your needs as they evolve throughout the night. Ultimately, you need a system that can monitor and deliver the right temperatures in real-time as you sleep, like the Pod does.
Does everyone have the same ideal temperature targets?
So, we know that a person’s sleep temperature evolves throughout the night, depending on the stage of sleep and their own natural circadian rhythm. But if you could sync up everyone’s circadian rhythm and sleep stages, would all of our optimal sleep temperatures match up throughout the night?
It turns out that there is a lot of variation among individuals in their temperature needs and preferences. Scientists have found a range of temperatures under the covers among people when they sleep, up to 5-10°F, which indicates that different people have different “set points” for their sleeping temperature and energy requirements.
A 2005 survey also showed that personal preference for bedroom temperature was quite varied, as well. Responses indicated ideal temperatures ranging from below 60°F up to 75°F. Interestingly, the #2 most important factor the participants indicated for sleep quality, second to location of sleep, was the temperature.
Not only do different people have various sleeping temperature needs, but each person may themselves have a range of ideal sleeping temperatures. Temperatures further outside a person’s ideal range result in increased discomfort and more interrupted sleep, making it crucial for each individual to find the right temperatures to achieve the best sleep possible.
What about timing? Is there an ideal sleep temperature schedule for the best sleep?
Not even the timing of sleeping temperatures is consistent between people. A study from 2001 looked at the sleeping body temperatures of self-identified “morning-” and “evening people”. Between the two groups, it was found that they had different timing for their bodies reaching the lowest-temperature point, relative to when they woke up. The researchers also found that women experienced their temperature cycles a half-hour earlier than men did.
Remember that the time when the body reaches its lowest temperature affects the onset, duration, and quality of sleep. All these factors– being a morning/night person, male/female, and many others– make each person unique in their sleeping temperature profile.
"Not only do your temperature needs change throughout the night, but each individual has unique needs for their sleep temperature and timing."
So what can you tell me about my own optimal sleep temperature?
The takeaway here is that the personal nature of preferred sleeping conditions and individual physiology makes a one-temperature-fits-all solution impractical. Not only do your temperature needs change throughout the night, but each individual has unique needs for their sleep temperature and timing.
How can Eight Sleep help with regulating my sleeping temperature?
The technology behind Eight Sleep’s Pod is designed to learn and respond to your body’s temperature needs. The Pod’s advanced Sensing Technology layer detects your heartbeat, breathing patterns, temperature, and more to gather a full picture of your sleep profile. The Pod continually monitors and analyzes your sleep data with our Intelligent SmartTemp™ AI. Trained on over 70 million hours of sleep data, our SmartTemp™ algorithms learn over time what your body requires for better sleep, delivering the most ideal sleep temperature through the Pod’s Active Grid. Our technology also allows for dual-zone control, so the same level of temperature monitoring and control is available for both sides of the bed independently, since– as we know– everyone has unique sleeping temperature requirements.