Why sleep temperature matters

Why do I get hot and cold at night?

Are you sometimes hot and cold at night? Then you are one of many that struggles to stay in the ideal climatic comfort zone during the night. Find out what you can do to sleep better.

Why does sleep temperature matter? | Why am I hot and cold at night? | How can I keep the best temperature for sleep?

Hot and cold body temperature swings at night

The ideal climatic comfort zone

To fall asleep our core temperature needs to drop and our skin temperature needs to increase. To stay asleep and have the highest sleep quality we need to stay in the ideal climatic comfort zone. If our temperature fluctuates in particular our deep sleep phases suffer.

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.

Why does our temperature fluctuate

Hot and cold at night

There are many different factors that can cause our temperature to fluctuate during the night. Some of the most common ones are:

FOOD: have you eaten a heavy meal before going to bed? Some types of foods really are sleep killers. If your metabolism is working at full capacity during the night this can cause you to overheat.

DRINKS: drinking coffee or beverages with caffeine before going to bed can not only make us too energised to fall asleep, coffee can also increase our body temperature. Consuming too much alcohol can also cause night sweats. 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."

EXERCISE: doing sports has a positive impact on our sleep but if we are completing a hard workout just before going to bed our temperature can be elevated. This can make it more difficult to fall asleep and as our temperature drops during the night we could become cold.

HORMONAL CHANGES: women's sleep is impacted by hormonal changes throughout their lives. From menstruation to pregnancy and menopause these hormonal changes can lead to hot flashes at night and sudden temperature increases. Dr Rebecca Robins, (PhD, researcher Harvard Medical School) explains: ”Hot flashes are common during menopause, a life stage that unfortunately carries with it significant sleep difficulties for women. Those experiencing menopause commonly also report more insomnia than other life stages. Specifically, research shows that 61% report insomnia symptoms.”  

ILLNESS & INFECTION: infections can lead to fevers and as a result we overheat and start to sweat at night. If our sleepwear becomes wet we can afterwards become cold and start to shiver. Some other illnesses such as cancer, heart disease and chronic stress have also been linked with night sweats and fluctuating sleep temperatures.

OBSTRUCTIVE SLEEP APNEA: sleep apnea not only makes it difficult to breathe at night, it has also been linked to night sweats.

BEDROOM TEMPERATURE: a bedroom that is too hot or too cold can impact our sleep temperature during the night. During the REM sleep phases our natural thermo-regulation ability is impaired making it even more important to have the right ambient temperature when we sleep

BEDDING & SLEEPWEAR: bedding and sleepwear that aren't breathable can trap in heat making it easier to become overheated. As a result you start to sweat and if you have the wrong fabrics next to your skin you can become wet and cold. Professor Torbjörn Åkersted (Stockholm University) explains: "Sleep is vital. By understanding the factors that affect our sleep and by changing a few habits we can have a big impact on our sleep quality and wellbeing. Sleepwear and bedding that help to manage temperature and sweat during the night can support the body's natural thermo-regulation."

Hot and cold while sleeping

How can I keep the best temperature for sleep?

There are some changes we can make to our habits and sleep setting to avoid becoming hot and cold at night.


Have a light meal avoiding red meat and strong spices. Limit the consumption of alcohol and caffeine. If you tend to overheat at night you can keep a glass of ice water next to your bed to cool down.


Our bedrooms should ideally be below 18°c / 64.5°F whilst not so cold that we start to shiver. To keep your bedroom cool during the summer make sure to keep the blinds and windows closed during the day to avoid a heat build-up. Open the window at night once the temperature drops and if need use air conditioning or a fan.


Though it can be cozy to have our pets in the bed with us, more isn't merrrier when it comes to keeping a cool sleeping environment. It's best that pets as well as children sleep in their own beds at night.


The ideal bedding and sleepwear should be breathable so that any excess heat is released. If we start to sweat it should help to cool us down by working on two levels: firstly keeping us cool with the help of evaporative cooling. As the moisture is released to the air it creates a cooling effect on our skin. Secondly it should keep our skin dry with the help of moisture wicking. Look for natural and light materials that dry quickly. With the right sleepwear we stay longer in the ideal climatic comfort zone. That's why medical experts such as professor Michael Gradisar (sleep researcher and clinical sleep psychologist) recommend Dagsmejan; "I saw straight away that Dagsmejan sleepwear could balance one's environment with one's body. And I never expected their sleepwear to be so damn comfortable! "

The ideal sleeping temperature

Sleep better

Temperature regulating pajamas

The Dagsmejan Balance collection is developed to help you stay in the ideal climatic comfort zone at night. 6x more breathable than cotton this collection of temperature regulating pajamas is ideal if you are hot and cold at night. The Balance collection is also great at combatting night sweats, with 4x better moisture management than cotton you can experience the best pajamas for night sweats.

The Balance collection is made with beechwood fibres paired with a proprietary technology, helping you sleep better in a totally natural and sustainable way.