Night sweats

What are night sweats?

Sweating is a natural response by your body to prevent you from overheating. Sweat glands release sweat, a mix of water and other substances, through your skin. Heat is released as water evaporates from your skin, which cools your body down. Sweating is controlled by a part of your brain called the hypothalamus, which regulates your body temperature. The hypothalamus sends signals to over two million sweat glands to maintain the optimal body temperature. 

Night sweating is different from the body's normal response to overheating eg when it’s too hot in your bedroom or you're using a heavy blanket. Night sweats are episodes of excessive sweating (hyperhidrosis) while you sleep that leave you, your nightwear and your bedding soaking wet.

Night sweats can affect people of all ages — adults and children.

They often go away without the need for treatment but if you’re worried, see your GP.

In some cases, there is no particular reason for night sweats. In some cases, it is caused by hyperhidrosis, a condition that causes excessive sweating in the day and night — if it has no known cause it’s called idiopathic hyperhidrosis and if it has a known cause it is called secondary hyperhidrosis. 

Other common causes of excessive sweating at night are:

• Anxiety and stress — this can cause excessive sweating in the day and night
• Gastroesophageal reflux disease (GERD) — persistent acid reflux due to problems with the muscle that closes your oesophagus  
• Low blood sugar (hypoglycaemia) — you’re at a higher risk of developing low blood sugar if you have diabetes
• Low testosterone
• Menopause — night sweats due to menopause usually occur alongside other menopausal symptoms such as hot flushes in the day, mood changes and vaginal dryness
• Sleep apnoea — temporarily stopping breathing when sleeping; this is more common in men, occurring in one in four men

Other causes of night sweats include: 

• Side effects of certain medications — this includes: 
• Antipsychotics
• Diabetes medication
• Certain painkillers
• Hormone therapy drugs
• Selective serotonin reuptake inhibitors (SSRIs)
• Steroids
• Drug or alcohol abuse or withdrawal

Occasionally, night sweats can be a symptom of a serious underlying health condition, such as malaria, Hodgkin’s disease and cancer.

If night sweats are regularly disturbing your sleep and, as a result, you’re suffering from fatigue, see your GP.

You should also make an appointment with your GP if, along with night sweats, you also have:

• A cough
• A very high temperature and/or feel feverish
• Regular bouts of diarrhoea
• Unintentional weight loss

Your GP will ask about your general health and any family history of excessive sweating or night sweats. They may arrange tests to check for any underlying reasons for your sweating and, if needed, will arrange appropriate treatment.

In many cases, medical treatment isn’t needed for night sweats. If treatment is needed it will depend on what’s causing your night sweats eg you may need to correct a hormone imbalance or have your existing medications adjusted.

How to stop night sweats 

To manage excessive sweating at night, there are things you can try, including:

• Avoiding possible triggers such as alcohol, spicy foods and caffeine, especially two to three hours before bedtime
• Exercising regularly but not too close to bedtime
• Keeping your bedroom cool eg using a fan or air conditioning
• Losing any excess weight and eating a healthy diet, which is low in fat and sugar
• Practising relaxation techniques — this can help reduce anxiety or stress and can be done throughout the day but also before bedtime and after waking from a night sweat
• Wearing loose-fitting nightclothes and using bedding made from natural materials

To prevent dehydration, you can also drink lots of water. 

Your GP or consultant can suggest other ways to control excessive sweating at night, such as using clinical-strength antiperspirants before bedtime on your back, chest, feet, groin, hairline, hands and underarms. 

They may also recommend treatments for any underlying medical conditions. 

If your night sweats are menopausal, they may discuss treatment to relieve your menopause symptoms, such as hormone replacement therapy (HRT).

If your night sweats are a side effect of medication, your doctor may change your medication or alter the dosage.

If anxiety is causing your night sweats, you may be referred for anxiety treatment, such as cognitive behavioural therapy (CBT).

Hot flushes are sudden feelings of warmth, which can happen during the day or night. If they happen at night and cause you to sweat excessively, they are called night sweats. 

Night sweats are therefore sometimes called hot flushes. However, hot flushes are not the same as flushing. Flushing is reddening of the skin caused by increased blood flow — this can occur alongside night sweats but do not itself cause excessive sweating.