Too hot to sleep

why do i get hot when i sleep?

Do you tend to get hot at night? Then you are in 1 in 4 people that tend to overheat at night. In particular during the hotter months sleeping cool can be difficult, but also other factors can make us overheat at night. Read more about it and what you can do to enjoy a cool night's comfort.

Why do I get so hot when I sleep? | How does being hot at night impact my sleep? | How can I enjoy a cool night's sleep?

The causes

why do I get so hot when I sleep?

There are a number of factors that can cause us to overheat at night. Some of them might be medical in which case you should contact your doctor. By understanding why we are hot at night we can begin to find the solutions for cooling down.


If you have eaten a heavy meal, red meat or other types of foods that are difficult to digest just before going to bed you keep your metabolism awake at night. This can cause us to overheat. Some drinks that contain caffeine can also elevate our body temperature at night and too much alcohol can lead to night sweats and overheating. As Dr med Lutz Graumann puts it: "A no-go for good sleep is alcohol. The moment we drink alcohol, there is absolutely no restorative sleep. You can even see that your resting heart rate is elevated by up to 10 beats the whole night just because it."


Being physically active is closely linked to a good night’s sleep however, if we are exercising too close to bedtime our body temperature can be elevated making it difficult to fall asleep and to enjoy the best temperature for sleep.


When we are feverish our body temperature rises and we can start to sweat at night. If our bedding or pjs become wet this can lead to cold sweats as we become uncomfortably cold and start to shiver. There are a number of illnesses like chronic stress, cancer and heart disease that can lead to overheating at night. If you think you have a medical problem please contact your doctor.


Hormonal changes can impact in particular women’s sleep, from menstruation to pregnancy and menopause. These changes can lead to hot flashes and overheating at night.


If the ambient temperature is too high we easily overheat at night. Our bedrooms are actually on average 5ºC/ 41 °F warmer today than they were 5 years ago. During the REM sleep phases, the dream phases, our natural thermo-regulation ability is impaired making it even more important to have the right room temperature when we sleep. Dr Rebecca Robins, (PhD, researcher Harvard Medical School) explains: ”A warm room being good for sleep is actually a myth, although believed by many. A cool temperature is absolutely essential for sleep, as a low core body temperature is associated with shorter sleep onset, but also, a warmer environment causes more sleep fragmentation and nightmares.”


Bedding and sleepwear that aren't breathable can trap in heat making it easier to become too hot to sleep. As a result you start to sweat and if you have the wrong fabrics next to your skin you can become wet and cold. This is important all year, but having the best summer pajamas is particularly key as the ambient temperature is higher.

the impact


Temperature has a huge impact on our sleep quality and duration. As Dr med Lutz Graumann puts it: "Thermoregulation is key for a good night's sleep. To fall asleep and to enjoy a deep, restorative sleep we need for our core body temperature to drop, but if we get too cold we will shiver and our sleep quality suffers."

If we get too hot at night we will start to sweat while sleeping and if our sleepwear gets wet we often become cold afters starting to shiver. To stay in the restorative, slow-wave sleep phases temperature regulation plays a big role. It's in these sleep phases that we get the most rest.



Dagsmejan's Stay Cool sleepwear is designed to keep you sleeping soundly even when the temperature rises. The cooling nightwear is 8x more breathable than cotton and dries in 1/3 of the time. Made with botanic fibres from eucalyptus combined with the latest textile technologies this ultra-light sleepwear keeps you cool even in the hottest months.