Night sweats and can't sleep? Causes, what to do at 3 a.m., and what helps
Night sweats are repeated bouts of heavy sweating in sleep, enough to dampen or soak your night clothes or sheets, and they're one of the most common reasons adults wake in the night. The usual causes are menopause and perimenopause, medicines (especially some antidepressants), alcohol, infections, low blood sugar, an overactive thyroid and sleep apnea; a hot room or heavy bedding is the simplest one. New, drenching sweats with fever, weight loss or swollen glands need a doctor soon.
The sweat itself is often only half the problem. Many people fall into a second pattern: they wake soaked, cool down, then lie awake for an hour worrying about the next one. Below: the causes and how to tell them apart, what to do the moment you wake, how to get back to sleep, how to set up the bed, the treatments doctors use, and the signs that mean see someone.
Night sweats vs just sleeping hot
Waking a bit warm under a thick duvet in a heated room isn't really night sweats. Doctors usually mean sweating heavy enough to wet your clothes or sheets, often with a hot rush first, that happens even when the room is cool. A quick test: drop the room to around 60 to 67°F (15 to 19°C), swap to a light breathable cover and cotton or linen night clothes for a week. If the sweating stops, it was the bedroom. If it carries on, look at the causes below.
Common causes, and a sign for each
| Cause | Signs that point to it | What to do |
|---|---|---|
| Perimenopause and menopause | Women around 40 to 55; a rush of heat over the chest and face, then sweat, then a chill; changes in periods; hot flashes in the day too | Bedroom and habit changes below; talk to a doctor about hormone and non-hormone treatments |
| Medicines | Started or changed a medicine around when it began. Common ones: SSRI and SNRI antidepressants, some diabetes medicines, steroids, hormone treatments for breast or prostate cancer, some pain and fever medicines | Ask your prescriber; don't stop a medicine on your own |
| Alcohol | Worse on nights you drink, especially within 3 hours of bed; also with alcohol withdrawal | Try 2 alcohol-free weeks and compare |
| Low blood sugar at night | On insulin or some tablets for diabetes; vivid dreams, headache or confusion on waking | Check with your diabetes team soon |
| Infection | Feeling unwell, fever, cough; tuberculosis and some other infections can cause night sweats for weeks | See a doctor if it lasts more than a few days or comes with fever |
| Overactive thyroid | Feeling hot all day, fast heartbeat, shaky hands, weight loss, anxiety | A blood test with your doctor |
| Sleep apnea | Loud snoring, gasping or pauses in breathing, waking with a dry mouth or headache, very sleepy in the day | Ask for a sleep study |
| Anxiety and panic | Waking with a pounding heart, fear or racing thoughts as well as sweat | See our guide on waking at night with anxiety |
| Acid reflux | Heartburn, sour taste or cough at night | Earlier, lighter dinner; raise the head of the bed; ask a doctor |
| Idiopathic hyperhidrosis | Heavy sweating day and night for years, with no other cause found | A doctor or dermatologist can offer treatments |
| Less often: lymphoma and other cancers | Drenching sweats with unexplained weight loss, fever or swollen glands | See a doctor soon, within days |
For most people the cause is one of the first four. But the list is why new night sweats with no clear reason should be checked once by a doctor.
What to do when you wake up soaked
Set this up before bed so you can do it half asleep, without bright lights or decisions.
- Don't check the time. Seeing "3:40" starts the counting and worry that keep you up longer than the sweat does.
- Cool down fast. Throw off the cover, turn the pillow to the cool side, put your feet out.
- Change quickly in dim light. Keep a spare set of night clothes and a towel on the bedside table. Lay a second towel or a thin waterproof sheet over the damp patch if changing the bed would wake you fully.
- Sip cool water from a glass you put by the bed.
- Breathe slowly for a few minutes: in through the nose for 4 counts, out for 6. Some hot-flash programmes use slow paced breathing as the flush starts.
- Lie back down. If you drift off, good. If you're still wide awake and alert after what feels like 20 minutes, go to the next section.
How to get back to sleep after a night sweat
A hot flash usually lasts a few minutes. What turns it into an hour awake is what happens next: frustration, clock-watching, and lying in bed alert. Over weeks, that teaches the brain that waking at 3 a.m. means being awake until 5. That's how a hormone problem turns into a sleep problem.
- Get up if you're alert. Go to another room with a dim lamp and something calm (a paper book, a puzzle), and come back to bed when sleepy. This is the core rule of stimulus control.
- Keep the same wake-up time the next morning, even after a bad night. Lie-ins make the next night lighter.
- Don't stay in bed longer to make up for it. Extra time in bed tends to fill with more waking, not more sleep.
- Talk back to the 3 a.m. thought. "I'll be wrecked tomorrow" is common and usually overstated. Write it down in the morning and see what really happened.
- No phone. Light and messages wake you further.
If the sweats have settled but you still wake and lie there, the sweat may have started the pattern and habits are keeping it going. Our guide on how to stop waking up at night covers that.
Set up the bed and bedroom
- Room: cool, around 60 to 67°F (15 to 19°C), with a fan for moving air. A window cracked open if it's safe and quiet.
- Layers instead of one heavy duvet: a sheet plus a light blanket you can push off and pull back.
- Breathable fabrics: cotton, linen or moisture-wicking night clothes; some people sleep better in less.
- Pillows: a spare cool pillow to swap to, or a pillow cover you can flip.
- Within reach: water, a spare top, a small towel, a fan with a quiet setting.
- Partner: separate covers often help when one of you runs hot.
Habits that can make night sweats worse
- Alcohol, especially in the evening. It widens blood vessels and makes the second half of the night lighter and more broken.
- Spicy food and big, late meals. Eat dinner at least 2 to 3 hours before bed.
- Caffeine after midday, which can trigger flushes in some people and makes sleep lighter for most.
- Smoking is linked to more hot flashes.
- A very hot bath or shower right before bed. A warm one 1 to 2 hours before is fine.
- Hard exercise late at night. Regular exercise earlier in the day is good for sleep.
Not every trigger affects everyone. Use the diary below to find yours.
A 2-week night sweat diary
Write a line each morning for 14 days. It shows patterns quickly and is the most useful thing you can bring to a doctor.
| Column | What to note |
|---|---|
| Sweats | How many, roughly when, how bad (1 damp, 2 changed top, 3 changed sheets) |
| Sleep | Roughly when you fell asleep, how long you were awake after each sweat, when you got up |
| Evening | Alcohol, caffeine, spicy food, late meal, room temperature |
| Body | Fever, weight change, cough, period dates, hot flashes in the day |
| Medicines | Anything new or changed, including supplements |
What doctors can offer
Treatment depends on the cause, so the first step is finding it: often a talk, an exam, and blood tests (thyroid, blood count, blood sugar, sometimes infection tests). For menopause and perimenopause, options include:
- Hormone therapy (oestrogen, with progestogen if you have a uterus) is the most effective treatment for hot flashes and night sweats. It's not right for everyone; your doctor weighs your age, time since your last period and your health history.
- Non-hormonal medicines: some SSRI and SNRI antidepressants at low doses, gabapentin, and newer non-hormonal pills, fezolinetant (FDA-approved in 2023) and elinzanetant (approved in 2025).
- CBT and clinical hypnosis: the Menopause Society's 2023 non-hormone statement recommends both for hot flashes. CBT for insomnia, a separate programme, targets the sleep problem that night sweats often leave behind.
If a medicine is the cause, a prescriber may change the dose, timing or drug. Treating sleep apnea, reflux, thyroid problems or an infection usually settles the sweats that come with them. More detail for midlife women is in our guides to perimenopause insomnia and menopause sleep problems.
When to see a doctor
See a doctor soon (within days) if night sweats come with any of these:
- fever, or feeling unwell;
- weight loss you can't explain;
- swollen glands in the neck, armpits or groin;
- a cough that won't go, or coughing up blood;
- confusion, shaking or headache on waking if you take diabetes medicine.
Make a routine appointment if night sweats are new and you don't know why, go on for more than 2 to 3 weeks, started after a new medicine, or wreck your sleep most nights. Seek urgent help for chest pain, trouble breathing or fainting.
Frequently asked questions
Why do I get night sweats but I'm not in menopause?
Common reasons are medicines (especially antidepressants), alcohol, a warm room, infections, low blood sugar, thyroid problems and sleep apnea. Men get night sweats too. If you can't find an obvious cause, see a doctor.
Can anxiety cause night sweats?
Yes. Anxiety and panic can wake you hot, sweaty and with a racing heart. If that's the pattern, our guide on waking at night with anxiety has what to do in the moment.
How long do menopause night sweats last?
For many women hot flashes and night sweats go on for several years; in a large US study (SWAN), the median length of frequent hot flashes was about 7.4 years. Treatments can reduce them a lot in the meantime.
Should I sleep with a fan on?
A fan that moves air across the bed helps many people cool down faster after a sweat. Choose a quiet one, or one with a low steady setting.
Why can't I get back to sleep after a night sweat?
The heat and the change wake you up fully, then frustration and clock-watching keep you awake. Cool down fast, don't check the time, and if you're still alert after about 20 minutes, get up until you're sleepy again.
Tonight
Set the room cool, swap to layers, put a spare top, a towel and water by the bed, and turn the clock away. Start the diary tomorrow morning. If the sweats have left you lying awake even on good nights, the free 2-minute sleep quiz works out your minutes awake in bed and a starting sleep window. For more on sleep in midlife and night waking, see all our sleep guides.
Sources: The 2023 nonhormone therapy position statement of The North American Menopause Society, Menopause, 2023. The 2022 hormone therapy position statement of The North American Menopause Society, Menopause, 2022. Avis NE et al., Duration of menopausal vasomotor symptoms over the menopause transition (SWAN), JAMA Internal Medicine, 2015. US Food and Drug Administration, approval of Veozah (fezolinetant), May 2023, and Lynkuet (elinzanetant), October 2025. Mold JW et al., Night sweats: a systematic review of the literature, Journal of the American Board of Family Medicine, 2012. NHS, Night sweats. Edinger JD et al., AASM clinical practice guideline on behavioural treatments for chronic insomnia, 2021. This guide is education, not medical advice.