Why Am I So Hot at Night? The Science Behind Feeling Too Warm in Bed

It is 3am. You kick off the duvet, flip the pillow to the cool side, and lie there wondering why your body feels like a small radiator when all you want is sleep.

Waking too warm is a common reason for broken nights, and it is rarely just bad luck. There are well understood reasons why it happens, and most of them are things you can change. This guide covers why you overheat at night, what makes it worse, and what to try first.

Why temperature matters for sleep

Your body temperature naturally drops in the evening as part of how it prepares for sleep. To shed that heat, blood vessels in your hands and feet widen, which is why you can feel warmer in the evening just as your body is trying to cool down.

When the room or the bed holds that heat in, your body has to work harder to cool, and waking hot becomes more likely. Many UK homes hold the day's warmth well into the night, especially upstairs bedrooms with the heating on.

The most common reasons you overheat at night

A warm bedroom

The Sleep Charity suggests an ideal bedroom temperature of around 16 to 18°C. Many UK homes run warmer than that in the evening, particularly in winter and on warm summer nights.

Your bedding

Polyester and microfibre tend to hold heat. Cotton is breathable but absorbs sweat and holds it against the skin, which can leave the bed feeling warm and damp. A heavy duvet on all year adds to the problem.

Hormonal changes

Perimenopause and menopause, the menstrual cycle, pregnancy and thyroid conditions can all make you run warmer at night. If hormonal night sweats are the main issue, our guide to bedding for menopause night sweats goes into more detail.

Alcohol and caffeine

Alcohol can make you drowsy but tends to make sleep lighter and more broken later in the night. The NHS suggests avoiding alcohol for one to two hours before bed, and the Sleep Charity suggests avoiding caffeine for around eight hours before bed.

Late, heavy meals

Eating a large meal close to bedtime means your body is still busy digesting when it would rather be winding down. An earlier, lighter evening meal is an easy change to try.

Stress and a busy mind

Carrying the day's worries to bed keeps you alert, and a restless, wakeful night often feels like a hot one. A calmer hour before bed can make a real difference to how the night starts.

A note on mattresses and duvets

Dense foam mattresses can hold body heat beneath you, and a winter-weight duvet used in summer is one of the simplest causes of overheating to fix. A lighter duvet in warm months, or two thinner layers you can adjust through the night, gives you more control.

How to stop overheating at night

Cool the room

• Check the temperature with a simple room thermometer and aim for around 16 to 18°C.
• Turn the heating down an hour or so before bed.
• Open a window in the evening if it is safe to, then close it once the room has cooled.
• In summer, keep curtains or blinds closed during the day so the room does not heat up.
• A fan helps air move, and many people find its steady sound easy to sleep through.

Change what touches your skin

• Choose a breathable fabric that moves moisture away from the skin rather than holding it. Eucalyptus lyocell sheets do both.
• Match the duvet to the season rather than leaving one on the bed all year.
• If you share a bed with someone who runs cooler, two separate duvets let you each choose your own weight.

Adjust the evening

• Move your last caffeine earlier in the day.
• Leave a gap between your last drink and bedtime.
• Eat your evening meal a little earlier.
• A warm bath or shower as part of a calm wind-down suits many people.

Where eucalyptus lyocell fits

Eucalyptus lyocell is the fabric we chose for The Sheets. For hot sleepers, the qualities that matter are these:

• The structure of the fibre carries heat away from the body.
• It moves moisture away from the skin, so the surface stays drier through the night.
• No cooling treatments are applied, so there is nothing to wash out.
• It machine washes at 30 degrees and gets softer with every wash.

Bedding will not change a warm room or a hormonal cause, but it is the part of the bed you are in contact with all night, and the easiest part to change.

Hot at night but not sweating

Feeling hot without sweating usually points to your surroundings: a warm room, a heavy duvet or bedding that holds heat. Hormonal changes, thyroid conditions and some medications can also play a part. If it carries on after you have cooled the room and changed your bedding, speak to your GP.

When to speak to your GP

If you have made changes to your bedroom and evening habits and are still waking hot or sweating, it is worth speaking to your GP. Persistent or drenching night sweats can have causes that are worth checking, including thyroid problems, infections, medications and hormonal changes. If you are in perimenopause or menopause, your GP can talk you through the options available.

Questions Dreamers ask

Why do I get so hot at night when the room is cool?

If the room is cool and you still overheat, look at your bedding, hormonal changes, or evening habits such as alcohol or a late meal. Bedding that holds heat and moisture can leave you warm even in a cool room. A breathable fabric that moves moisture away from the skin, such as eucalyptus lyocell, is worth trying.

Why am I always hot at night?

If you run hot most nights, look at what stays the same: your bedding, your mattress, your duvet and your room temperature. A cooler room, a lighter duvet and breathable sheets address the things most within your control.

Is it normal to sweat at night?

Some sweating during sleep is part of how your body regulates its temperature. Waking regularly drenched is worth looking into. If changes to your room and bedding do not help, speak to your GP.

Does alcohol make you hotter at night?

Alcohol can make you drowsy but tends to make sleep lighter and more broken later in the night. The NHS suggests avoiding alcohol for one to two hours before bed.

What is the best bedroom temperature for sleep?

The Sleep Charity suggests an ideal bedroom temperature of around 16 to 18°C. Many UK homes are kept warmer than this in the evening, so turning the heating down before bed often helps.

What sheets are best for hot sleepers?

Look for a breathable fabric that moves moisture away from the skin rather than holding it. Eucalyptus lyocell carries heat away from the body and moves moisture away from the skin, and it washes easily at 30 degrees.

Read next: cooling sheets for hot sleepers