What causes night sweats?

We have all had it, as adults or as children – waking up in the night to find yourself drenched in sweat.

It can often be down to something trivial – and easily solved - such as your bedroom being too warm, or your blanket or duvet being too heavy.

Sweating is a very normal way for your body to regulate its temperature, helping to release heat by evaporation if your core temperature rises too high.

If you have checked your sleep environment, changed something that has stopped your sweating and there are no repeated episodes, then they are not labelled as night sweats and typically are not a sign of a medical problem.¹

The most common causes of night sweats

Here are the most common causes of a sweaty night’s sleep:³

• Hormones

Hormone concerns and changes can be related to night sweats.

Sweaty nights are often reported as a side effect of the menopause, thought to be brought on by significant changes in the female production of certain hormones.

Find out more about ‘What exactly is the menopause’ in our Health Hub article. Hormones are not responsible for causing night sweats in just women - there are many hormone-related reasons that can cause night sweats in men too.⁴

• Low blood sugar (hypoglycaemia)

Those who need to take insulin or diabetes medications may find they have hypoglycaemia (also called a “hypo”) at night, and this can be accompanied by sweating.⁵

• Anxiety

Feelings of anxiety, fear and panic can have a huge impact on your sleep.

If you are suffering from anxiety, this could be at the root of your night sweats. Read more about how to sleep better if you suffer from anxiety.

• Medications

Some antidepressants, steroids and painkillers, as well as many other drugs, can cause night sweats or flushing.

Speak to your GP if you think your medication is causing night sweats, and consult with your GP before stopping any medications.

• Alcohol or drug use

Both alcohol and drugs can cause your body temperature to spike, and therefore induce night sweats, especially when consumed in the evening.⁶

• Infection

As your body’s temperature rises to fight off infections, it makes sense that this can disturb your sleep with night sweats.

Speak to your GP if you have any concerns about an infection you may have.⁷

• Hyperhidrosis

Finally, night sweats are often caused by hyperhidrosis, which can be a harmless condition that makes you sweat too much.⁸

Things you can do to help with hyperhidrosis (excessive sweating)

You may find that hyperhidrosis gets better with age, but there are also things you can do, such as wear loose-fitting clothing and moisture absorbing and breathable footwear.

Drinking alcohol or eating spicy food may also trigger sweating, so try avoiding these if you find they contribute to night sweats.⁹