It is 3am. You kick off the duvet. You flip your pillow to the cool side. You lie there, wide awake, wondering why your body seems to be generating the heat of a small radiator when all you want to do is sleep.
Feeling too hot at night is one of the most common sleep complaints in the UK, and one of the most disruptive. Even without fully waking, overheating pulls you out of deep, restorative sleep and leaves you exhausted in the morning.
The good news is that overheating at night is rarely just bad luck. There are specific, well-understood reasons why it happens, and most of them are fixable.
Why your body temperature matters for sleep
Sleep and body temperature are deeply connected. As you prepare for sleep, your body initiates a process called thermoregulation, which starts by lowering your core temperature by around 1 to 2°C. This cooling process is not incidental. Your brain uses it as the signal that it is time to sleep.
When your environment or your bedding prevents this cooling from happening effectively, your sleep suffers. You take longer to fall asleep, spend less time in deep sleep, and wake more frequently through the night.
Feeling hot at night is not just uncomfortable. It is genuinely disruptive to the architecture of your sleep.
The most common reasons you overheat at night
Bedroom temperature
The ideal sleep temperature is 16 to 18°C. Most UK homes run significantly warmer, particularly in winter and during increasingly warm summers.
Your bedding
Synthetic fabrics trap heat and moisture. Cotton absorbs sweat but holds it against the skin. Both prevent your body from regulating itself through the night.
Hormonal changes
Menopause, perimenopause, the menstrual cycle, pregnancy, and thyroid conditions can all cause the body to run significantly hotter at night.
Alcohol and caffeine
Both raise core body temperature. Alcohol disrupts sleep architecture through the night. Caffeine has a six-hour half-life, meaning a 4pm coffee still affects sleep at 10pm.
Late meals
Digestion generates significant body heat. Eating within two to three hours of sleep means your body is actively processing food when it should be cooling down.
Stress and anxiety
The sympathetic nervous system raises heart rate, blood pressure, and body temperature. Carrying the day's worries to bed activates this response, making overheating harder to resolve.
A note on your mattress and duvet
Memory foam mattresses are particularly prone to heat retention. The dense foam traps body heat beneath you rather than dissipating it. Duvets above 10.5 tog are generally too heavy for year-round use in UK bedrooms, particularly for hot sleepers.
How to stop overheating at night
Cool your bedroom
- Aim for 16 to 18°C. Use a thermometer to check, you may be warmer than you think.
- Keep windows open in the evening to let cool air in, then close before sleeping.
- Use a fan, not just for the breeze but for the white noise, which also supports deeper sleep.
- Keep curtains or blinds closed during the day in summer to stop the room heating up.
Switch your bedding
- Replace synthetic or cotton sheets with naturally cooling fabric. Eucalyptus lyocell is particularly effective because it actively wicks moisture away from the skin and regulates temperature rather than trapping heat.
- Use a lighter duvet 4.5 to 7.5 tog for summer, 10.5 for winter.
- Consider a separate duvet if you share a bed with someone who runs cooler. Different tog ratings mean different sleeping temperatures.
Adjust your evening habits
- Stop caffeine by 2pm. Give your body time to metabolise it before sleep.
- Avoid alcohol within three hours of bed. It raises body temperature and fragments sleep.
- Eat earlier. Finish your last meal at least two to three hours before sleep.
- Have a warm shower or bath 90 minutes before bed. The subsequent drop in body temperature promotes sleep onset.
When to speak to your GP
If you have made changes to your sleep environment and habits and are still experiencing significant night sweating, it is worth speaking to your GP. Persistent night sweats can occasionally be associated with underlying conditions including thyroid disorders, infections, certain medications, or hormonal changes that may benefit from medical support.
This is particularly relevant for menopausal and perimenopausal women. There are now excellent evidence-based options available for managing temperature-related sleep disruption, and your GP can help you navigate them.
Frequently asked questions
Why do I get so hot at night even when the room is cool?
If your room is cool but you are still overheating, the most likely causes are your bedding fabric, hormonal factors, or evening habits such as alcohol or a late meal. Synthetic and cotton fabrics trap heat against your body even in a cool room. Switching to a naturally cooling, moisture-wicking fabric like eucalyptus lyocell can make a significant difference even without changing your room temperature.
Is it normal to sweat at night?
Some sweating during sleep is normal. Your body uses perspiration as part of its temperature regulation process. However, waking regularly in a sweat or feeling damp and uncomfortable through the night is not something you have to accept. It is usually a sign that your sleep environment is working against your body rather than supporting it.
Can anxiety cause overheating at night?
Yes, significantly. Anxiety activates your sympathetic nervous system, which raises heart rate, increases blood flow, and elevates core body temperature. For people who experience anxiety at bedtime or through the night, this physiological response can cause significant overheating that is directly linked to their mental state rather than their environment. Creating a calm, relaxing sleep environment can help reduce this response.
Does alcohol make you hotter at night?
Yes, alcohol raises core body temperature and disrupts your body's thermoregulation through the night. It also fragments sleep, reducing time in deep restorative stages. Many people find that cutting alcohol consumption in the evenings has an immediate and significant impact on night sweating.
What is the best temperature for sleeping in the UK?
The widely recommended range is 16 to 18°C. This feels cooler than most UK homes, particularly in winter, but even a small reduction from 22 to 18°C can have a noticeable positive effect on sleep quality. Combined with breathable, cooling bedding, a cooler room gives your body the best environment for deep and uninterrupted rest.
What sheets are best for hot sleepers in the UK?
Eucalyptus lyocell is widely considered the best fabric for hot sleepers. It is naturally temperature-regulating and moisture-wicking, actively drawing heat and sweat away from the skin rather than trapping it. Unlike cotton, which absorbs moisture and holds it against the body, eucalyptus lyocell allows moisture to evaporate quickly, keeping you cooler and drier through the night.