Hot flushes and night sweats: causes and what helps

What is a hot flush?

A hot flush is a sudden feeling of intense heat that usually starts in the chest and spreads up to the neck and face. Your skin may redden, you may sweat heavily, and your heart may race. Some women feel anxious, dizzy or sick during a flush, then chilly and shivery as it passes. A flush typically lasts from a few seconds to several minutes.

They can happen a few times a week or many times a day, and are the symptom most closely associated with menopause. Doctors call hot flushes and night sweats together "vasomotor symptoms".

What causes hot flushes?

The body’s thermostat sits in a part of the brain called the hypothalamus. Normally it allows a comfortable range of core temperatures before it reacts. As oestrogen falls and fluctuates in perimenopause, that range narrows. A tiny rise in body temperature – one you would not usually notice – is then read as overheating.

The brain responds as if you were far too hot: blood vessels in the skin widen to release heat (the flush), sweat glands switch on, and the heart speeds up. Once the heat is lost, you may feel cold. Researchers have identified a group of nerve cells in the hypothalamus, regulated by oestrogen, that drives this response – which is how some newer non-hormonal medicines work.

Common triggers include hot drinks, caffeine, alcohol, spicy food, smoking, warm rooms and stress. For more on what oestrogen does, see oestrogen.

What are night sweats?

Night sweats are hot flushes that happen while you sleep. They are more than feeling warm under a heavy duvet: your nightclothes and bedding can be soaked even though the room is cool. They often wake you up, and that broken sleep can leave you tired, irritable and less able to concentrate the next day.

What causes night sweats?

Menopause is one of the most common reasons for night sweats in women in their 40s and 50s, but it is not the only one. Other common causes include:

• anxiety
• medicines, including some antidepressants, steroids and painkillers
• low blood sugar (hypoglycaemia), for example in people with diabetes
• alcohol or drug use
• an overactive thyroid
• infections
• hyperhidrosis, a harmless condition that causes excessive sweating

How common are hot flushes?

Hot flushes are very common: most women have them at some point during the menopause transition, and for a significant minority they are severe enough to disrupt work, sleep and daily life. Some women from Black ethnic backgrounds are more likely to have hot flushes that are more severe and last longer.

How long do hot flushes last in menopause?

A single flush usually lasts a few minutes. The phase of life in which you get them is much longer: hot flushes and night sweats typically continue for several years, peaking around the final period and in the first year or two afterwards. The NHS says menopausal symptoms usually last for 7 to 9 years, and sometimes longer.

Can you get hot flushes after menopause?

Yes. Because flushes often peak around and just after the final period, many women continue to have them for several years into postmenopause, and a minority still have them in their 60s and beyond. They can also return when HRT is stopped. If flushes start for the first time long after menopause, see your GP, as other causes are more likely.

How can you reduce hot flushes and night sweats?

Simple changes can make flushes less frequent or easier to cope with:

• Dress in layers of light, breathable fabrics such as cotton or linen, so you can strip off quickly.
• Keep your bedroom cool – open a window, use a fan, choose lighter bedding and keep a glass of cold water by the bed.
• Cool down fast with a cold drink, a cool shower or a handheld fan.
• Notice your triggers and cut back on caffeine, alcohol, hot drinks and spicy food.
• Stop smoking.
• Exercise regularly and keep to a healthy weight – flushes tend to be worse with a higher body weight.
• Manage stress with breathing techniques, yoga or meditation.

Cognitive behavioural therapy (CBT) has good evidence for helping women cope with hot flushes and night sweats, and menopause-specific CBT programmes are available through the NHS and as self-help.

What treatment is available for hot flushes?

If flushes are affecting your sleep, work or wellbeing, talk to your GP. Treatment is decided with a doctor based on your health and history:

• Hormone replacement therapy (HRT) is the main treatment for hot flushes and night sweats and works well for most women.
• Non-hormonal prescription medicines are an option if you cannot take HRT or prefer not to. They include clonidine and certain antidepressants, and – for moderate to severe flushes when HRT is unsuitable – fezolinetant, which targets the temperature-control pathway in the brain.
• CBT, either alone or alongside medication.

Do herbal remedies help hot flushes?

Many plant products are sold for hot flushes, including red clover, soya and other sources of isoflavones, sage and black cohosh. Studies have looked at several of them, and the results are mixed: some trials found small effects, others none, and products vary widely in what they contain. None of them has an approved health claim for hot flushes or any other menopausal symptom.

The NHS notes that there is very little evidence on how well such remedies work or how safe they are, that their quality and ingredients cannot always be guaranteed, and that some – especially St John’s wort – can cause serious side effects when taken with other medicines. Always speak to your GP or pharmacist before trying a herbal remedy, especially if you take other medication or have had breast cancer.