You usually sleep best when your body is able to cool down a little in the evening. That sounds simple, but that is often exactly where things go wrong. A bedroom that is too warm, clammy bedding, cold feet or too much heat under your duvet can make you sleep more lightly, wake up more often and get up feeling less rested.
Luckily, there is a lot you can influence yourself. Once you understand what happens to your body temperature at night, you can adjust your bedroom and bed to match it in a smart way. That makes it calmer, drier and more comfortable without making it complicated.
Why warmth and coolness affect your sleep
Sleep and temperature are closely linked. In the evening, your core temperature naturally drops slightly. That is a normal part of your biological rhythm and helps your body switch from active to relaxed. That small drop makes it easier to fall asleep and supports deeper sleep.
If your surroundings are too warm, that natural process is disrupted. Your body then has to work harder to get rid of heat. You often notice this through sweating, tossing and turning, a clammy feeling or waking up more often. If it is too cold instead, energy goes into staying warm. That too can make your sleep more restless. The best nights usually do not happen in extreme cold or heat, but in a stable sleep climate. If overheating leads to recurring night sweats, see how to stop night sweats.
Practical guidelines you can use right away
| Part | Practical guideline | What this means |
|---|---|---|
| Daytime body temperature | Around 37.0°C | A normal baseline for many adults |
| Body temperature during sleep | Often about 36.2 to 36.5°C | Your body cools slightly at night to support sleep |
| Bedroom temperature | Usually 16 to 18°C | For many people, a comfortable range for sleeping well |
| Climate under the covers | Often comfortable around 33 to 35°C | Warm enough for comfort, without becoming stuffy |
| Humidity in the bedroom | Around 40 to 60% | Helps limit a stuffy or very dry feeling |
Think of these as guidelines, not hard rules. Some people prefer to sleep a little cooler, others a little warmer. How your bedding feels, how much you sweat and what time of year it is all make a difference.
What happens to your body temperature at night
In many people, core temperature drops by a few tenths of a degree during the night. That drop is linked to your internal clock. Your body gets ready for rest, heart rate and alertness go down, and the transition to sleep becomes easier. Especially in the first half of the night, that cooling helps you sleep more deeply.
If that natural cooling is blocked by a warm room, a heavy duvet, late exercise or a clammy bed, you often feel it straight away in your sleep quality. On the other hand, too much cold can lead to tense muscles, cold hands or feet, and waking up more often. So the aim is not to sleep as cold as possible, but at a temperature where your body does not have to keep correcting itself.
Your sleep climate consists of three layers
Your body
Your own body is the first factor. Hormones, age, stress, alcohol, spicy food, a warm shower at the wrong time, intense exercise late in the evening and illness can make you sleep warmer or colder. Partners also often differ a lot. One person likes to sleep cool, while the other gets cold feet quickly.
The climate under the covers
Between your skin, pyjamas, fitted sheet, mattress and duvet, a small microclimate develops. If heat and moisture cannot escape easily there, your bed can quickly feel stuffy or clammy. Thicker layers and less breathable materials in particular can make that worse. Materials that absorb and wick away moisture better often feel drier and calmer.
The bedroom itself
The room you sleep in is the third layer. Temperature, ventilation, sunlight and humidity together determine how fresh or stuffy it feels. A room can seem cool on paper, yet still feel unpleasant to sleep in if the air is still or if heat lingers in walls, curtains and bed textiles.
Sleeping too warm or too cold: where does it usually go wrong?
Why your body can feel hot in bed
A hot body during sleep often has a practical cause. Common triggers are:
- a bedroom that is too warm;
- a duvet that is too heavy or too insulating;
- bedding that holds on to heat and moisture;
- intense exercise shortly before bed;
- alcohol, a heavy meal or spicy food late in the evening;
- hormonal fluctuations, such as around menopause;
- stress or restlessness, which keeps your body more active.
If you mainly get warm around your head, neck or chest, also look at your pillow, pillowcase and how well your bed allows air to circulate. A bed that feels soft but still lets air through often feels much calmer than a bed that traps heat and feels closed in.
When cold disrupts your sleep
A bedroom does not need to be warm for comfortable sleep. But it can still become too cold. You usually notice that not from a thermometer alone, but from your body: shivering, stiff shoulders, cold feet, waking up to warm yourself up or constantly needing extra layers. For many people, sleeping below about 15 to 16°C feels less comfortable, although that differs from person to person. In that case, what often helps is not necessarily a much warmer room, but above all better layering in bed.
How to get your sleep temperature back in balance faster
Practical adjustments for tonight
- Keep your bedroom preferably around 16 to 18°C.
- Ventilate daily and keep heat out during the day with closed curtains or blinds.
- Choose layers rather than one very heavy duvet.
- Wear loose, breathable sleepwear.
- Avoid intense exercise in the last hour or two before going to sleep.
- A warm shower or bath earlier in the evening can help, because you often cool down more easily afterwards.
- Limit alcohol and heavy meals late in the evening if you tend to sleep hot or restlessly.
- If in doubt, measure the humidity too. A room that is too humid often feels stuffier than you think.
No air conditioner? These tips help you sleep cool without AC.
Bedding that feels more comfortable
If you tend to sleep hot, do not just look at the room temperature but also at the material against your skin. Fabrics that drape smoothly and wick away moisture better often feel drier and airier. At SJUMO, Tencel Sateen and Organic Cotton are especially interesting if you are looking for breathable, temperature-regulating bedding. If you mainly want lots of softness and easy care, Silky Smooth can feel pleasant. The best choice depends on how warm you sleep, how sensitive you are to clamminess and what feel you like most in bed.
When it makes sense to look beyond your bedroom
Sleeping hot or cold often has a logical cause in your surroundings or habits. However, if you regularly have severe night sweats, fever, noticeable temperature swings or your symptoms continue even though your sleep environment is in order, contact your GP. A blog can help with comfort and practical choices, but it does not replace personal medical advice.
Frequently asked questions
What is your body temperature when you sleep?
In many adults, core temperature drops slightly at night. During the day it is often around 37.0°C, and during sleep it often falls towards about 36.2 to 36.5°C. That drop is part of your natural sleep rhythm.
What is the normal temperature for sleeping?
For most people, the ideal bedroom temperature is around 16 to 18°C. Some studies mention a somewhat wider range, but this is a practical guideline that works well for many sleepers.
What temperature is too cold to sleep at?
There is no exact number for everyone, but many people sleep less comfortably below about 15 to 16°C. If you are lying there shivering, feel tense in bed or wake up because of cold feet, it is probably too cold for you.
Why does my body feel hot while I sleep?
That is often caused by a bedroom that is too warm, a heavy duvet, less breathable bedding, alcohol, exercising late, stress or hormonal fluctuations. If it keeps happening or comes with fever or severe night sweats, have it medically assessed.
Does a warm shower or bath help before bed?
It can, as long as you do not do it immediately before getting into bed. After a warm shower or bath, your body often cools down more easily, and that cooling can help you feel sleepier.
Which bedding feels comfortable if you sleep hot?
Many hot sleepers find breathable or moisture-wicking bedding more comfortable, such as Tencel or organic cotton. The bed then often feels less clammy and calmer. Also pay attention to duvet thickness, your pillow and ventilation in the bedroom.
If you want to feel a difference tonight, start small: make your bedroom a little cooler, ventilate well and choose cooling bedding that feels light, soft and breathable. That combination in particular often makes your bed feel calmer than simply lowering the thermostat.
