Night sweats
Sweating at night in a stuffy room or under a thick duvet is normal. Night sweats count as a symptom in a different situation: when sweat soaks your…
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Sweating at night in a stuffy room or under a thick duvet is normal. Night sweats count as a symptom in a different situation: when sweat soaks your nightclothes and bedding badly enough that they have to be changed, and it happens in a cool room with no outside cause. Behind it there is usually something harmless and easy to explain, but repeated episodes deserve looking into — particularly alongside other symptoms.
Common causes
- Menopause and perimenopause. Night-time flushes are among the most common causes in women from around 45;
- anxiety and stress, including night-time panic attacks;
- medication — antidepressants, hormone treatments, steroids, painkillers and fever-reducing drugs, diabetes medicines;
- low blood sugar overnight, more often in people using insulin or glucose-lowering tablets;
- infections, from an ordinary viral illness to tuberculosis and other prolonged infections;
- an overactive thyroid;
- sleep apnoea — pauses in breathing at night, usually with snoring and daytime sleepiness;
- acid reflux;
- alcohol and other substances, and withdrawal from them;
- hyperhidrosis, if sweating also bothers you during the day;
- lymphomas and some other cancers — an uncommon cause, but the one to exclude when weight loss and fever are also present.
When to see a clinician
- night sweats keep recurring and wake you;
- you are also losing weight without an obvious reason;
- there is fever, chills or a persistent cough;
- lymph nodes in the neck, armpits or groin have enlarged;
- you notice marked weakness, itching without a rash, or bone pain;
- the sweats began after starting a new medicine;
- you snore with pauses in breathing and feel sleepy during the day.
Night sweats together with unexplained weight loss and fever is a combination to act on rather than let run.
Rule out the room first
Before looking for an illness, it is worth making sure the cause is not the conditions you sleep in. A bedroom at roughly 17–19 °C suits most people. Synthetic bedding and heavy duvets hold heat; alcohol and spicy food a couple of hours before bed increase sweating, and so does hard exercise late in the evening. If the episodes stop after a week of changes, the question is answered.
What happens at the appointment
The clinician will ask how often this happens and for how long, whether you have to change the bedding, what other symptoms there are and what you take. They will examine your lymph nodes and thyroid. Blood tests are usual — a full blood count and biochemistry, inflammatory markers, glucose and thyroid hormones — and, if indicated, a chest X-ray and further investigations.
Keeping a short diary for two weeks is genuinely useful: dates of episodes, room temperature, what you ate and drank in the evening, what medication you took. This often identifies the cause faster than the blood tests do.
Treatment
There is no specific treatment for night sweats — the cause is what gets treated. For menopausal flushes, hormone replacement or non-hormonal options are discussed. If there is an anxiety disorder, that is addressed. Where a medicine is responsible, the clinician changes the drug or the dose. Infections, thyroid disorders and sleep apnoea follow their own pathways, and the sweating resolves along with the underlying problem.
Common questions
Do night sweats mean cancer? In the great majority of cases, no. Concern is justified when they come with weight loss, fever and enlarged lymph nodes.
Can it be purely stress? Yes — anxiety is a frequent cause, especially when episodes coincide with demanding periods.
I only sweat on my head and neck, is that the same thing? Localised night sweating relates more often to flushes or to the bedroom environment, but the approach to investigating it is the same.
Online consultation
In an online appointment a doctor can go through how often the episodes happen and what they are like, check the link with your medication and sleeping conditions, weigh up the warning signs, arrange the first blood tests and advise which specialist to see.
This article is for general information and does not replace a consultation with a doctor.
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Reviewed on Jul 3, 2026
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