Electric blanket

Health: about body temperature and sleep quality!

18 Jun, 2023
Jürgen Swinnen

A good night’s sleep is enormously important for our physical and mental health. Not surprisingly, many people want to know how to improve their sleep quality. Body temperature is one of the larger factors that affects your sleep quality. In this blog, we explain what temperature of your environment and body does to your sleep quality.

How important is temperature to sleep quality?

The temperature of your environment and of your body itself plays an important role when it comes to sleep quality. So many people can also easily gain here when it comes to their sleep.

Most people are unaware of what temperature does to their sleep. How warm it should be, as well as which blankets to use or when to sleep with the window open or closed, are all, sometimes crucial, factors that can improve your sleep quality.

The ideal sleeping environment

Your sleeping environment is the biggest factor where you can easily make gains in terms of temperature. Of course it should be comfortable, but what temperature your bedroom is is something that is often not thought about.

So what is the ideal bedroom temperature? Research shows that a constant ambient temperature of 18°C is best. At that temperature, your body gets the best quality of sleep possible.

There are a number of factors in your control to create the ideal sleep environment:

  • Keep your bedroom adequately cool in the summer. As mentioned, a room temperature of around 18 degrees is ideal.
  • Use the right blankets or duvets. If your bedroom is the right temperature, duvets that are too thick or too thin can disrupt your sleep, making you too hot or too cold. Bedding textiles are also best adapted to the season.
  • Provide a dark room while sleeping. The hormone melatonin helps you fall asleep easily; it is released when it gets dark. Bright light, especially blue (LED) light, interferes with its release.
  • Avoid screens from phones, tablets and televisions right before sleeping. This is because they emit a lot of this blue light. Certain devices and/or apps may install a night filter with more red light on your device.

What blanket should I get?

Of course, the most important thing is to have blankets or duvets that you feel comfortable with. A lot here depends on personal preference such as a heavy or a light blanket, a thin or a thick blanket. Make sure your blanket or duvet is not too hot or too cold for you. From both scenarios you wake up and your sleep cycle is interrupted.

It is best to choose a blanket made of natural materials such as cotton or wool, for example. These materials are strong in heat regulation, moisture control and naturally ventilate very well. Do you like to be warm? Then you can also go for a down comforter. With synthetic materials, your body often has a slightly harder time regulating its own temperature so they can feel too warm more quickly.

That doesn’t have to be a disadvantage, if you get cold faster of course. There are synthetic variants, such as ThinsulateTM, which imitate natural fibers. The advantage is that synthetic duvets are easier to wash yourself.

Can I sleep with my window open?

Many people like to sleep with their windows open or at least ajar. Is this good for your sleep quality? The answer is double. Indeed, properly ventilating the bedroom is important, and indeed it is best to do so with your windows wide open. But it is important, when it is cold outside, to close them back up. Your bedroom can warm back to 17 to 18 degrees in no time.

With an open window, you have less influence on the bedroom temperature. Also, wind or drafts can cool your bedroom, mattress and bed textiles too much. Also keep in mind that an open window can cause sleep to be disturbed by outside noises.

Especially during cold periods and especially during the winter season, it is best to close your windows completely during the day. And if you do like to open or ajar the window during the night, it’s best to do so just before you crawl into bed. That way, your bed textiles and mattress won’t be cooled down too much when you crawl into your bed. In the morning when you wake up, it is best to ventilate vigorously and briefly again and then close the windows. The temperature is rising again and warmer air can hold moisture better. This way you are less likely to have clammy sheets or condensation on the windows.

Why is temperature so important?

Sleep quality and body temperature are closely linked. The biological clock controls our body’s heat balance and ticks according to the circadian rhythm. This greatly determines our sleep-wake rhythm.

This automatic and independent cadence repeats itself day after day, ensuring that the core temperature of our body drops at night and rises again during the day. People who work irregular hours, do a lot of intercontinental travel or often do night work are very sensitive to the often abrupt adjustments to their internal biological clock. As a result, their sleep becomes greatly disturbed. Both men and women, younger people or older people, in short we all suffer from this.

Prolonged poor sleep has serious consequences for your health. The immune system weakens so you can get sick faster and the risk of cardiovascular disease increases greatly, according to several researchers. In these cases, always contact a doctor or sleep expert who can advise you.

The biological clock and body temperature

During the day and night, our body temperature is higher or lower. Differences in temperatures follow a natural rhythm. As we describe above, like an internal biological clock that, like the time clock, is divided into 24 hours. This is also known as the circadian rhythm.

Some of these processes that are automatically activated in our body by the various alarm clocks in the biological clock include: our body temperature, selected hormone release and slowing down or speeding up our metabolism.

Body temperature or skin temperature

In body temperature, we distinguish between core temperature and skin temperature. Core temperature is vital to us because the functioning of our organs, for example, depends on it. The body makes every effort not to have excessive temperature differences.

A degree more or less, it seems so trivial. But put just as simply, a core temperature above 38°C means that you have a fever and you often feel yourself really markedly less comfortable. When your body temperature drops below 35°C, we speak of hypothermia. Both situations describe only a few degrees of difference but can be life-threatening.

Your body responds with an important tool namely: the skin. So you start to shiver and thus warm up when you get cold and if the body wants to lower the heat then the ingenious action of perspiration kicks in and your body will be able to cool down the core temperature.

The core temperature rises during the day and falls again during the night, regardless of whether you are asleep or awake at that time. Admittedly, the differences will be less when measuring the core temperature. The skin surface temperature measurements are quite a bit larger at different times during the day. These changes in body heat are very important and affect our sleep-wake cycle.

When we go to sleep, our core body temperature drops by about one degree. This allows us to fall asleep easily. Around 4 a.m., this core temperature is lowest. The temperature then rises again in the morning when we wake up. During the late afternoon, this temperature reaches its peak.

Skin temperature rises as we sleep and balances with core temperature. You notice that when you go to bed later than your partner, for example, it’s like lying next to a heater.

Clearly, body temperature plays an important role in how well we catch sleep, how we sleep through and how smoothly we wake up again. Therefore, it is important to sleep in an environment where this natural process can take place unhindered. Not too cold or too hot in other words!


The temperature of the sleeping environment and of the body is an important and even controlling factor when we talk about sleep quality. This is where most people can make some gains. Keep your bedroom around 18 degrees and make sure you have the right blankets or duvets.

Most Frequently Asked Questions

A bedroom of 13 degrees is too cold in terms of temperature. Ideally, your bedroom temperature should be at 18 degrees. Below 15 degrees is definitely too cold.

The temperature of your bedroom should be around 18 degrees. This is slightly lower than we find comfortable during the day. A high bedroom temperature leads to sleep problems because you can’t properly catch sleep.