SWEATING is a normal part of the body’s cooling system.
It’s helps keep the body at the optimum temperature so all organs can work effectively.
Night sweats are trigger by a change to the body’s internal temperature
But waking up in the middle of the night with soaked through sheets is not normal – and in some cases can be a sign of something serious.
Night sweats are repeated episodes of intense sweating at night.
Many conditions trigger night sweating by changing the body’s internal temperature.
Most reasons for night sweats are harmless like a hot bedroom, or wearing too many layers.
But night sweats (especially in the colder months) can be a sign of an underlying condition such as menopause, an infection, disease or medication.
1. Menopause
Women are more likely to experience night sweats than men, largely because of the menopause.
Around 80 per cent of women going through the menopause suffer from hot flashes or night sweats, according to the National Institute of Health.
Writing in the Conversation, Professor Siobhan Banks, from he University of South Australia, said hot flashes associated with menopause are usually triggered by fluctuating levels of oestrogen.
The hormone is is thought it have an impact on the hypothalamus, part of the brain which regulates temperature.
2. ‘Male menopause’
Hormones can also cause night sweats in men, particularly those with low testosterone levels, known as hypogonadism.
Hot flashes plague up to 80 per cent of men with the condition, Harvard Health says.
According to the NHS, men who are born with condition can experience delayed puberty and small testes.
It can also develop in later life, particularly in men who are obese or have type 2 diabetes.
When it comes on in adulthood it is sometimes called the ‘male menopause’.
3. HIV
When our body is fighting an infection our internal temperature sometimes rises.
This can trigger sweating as the body attempts to cool itself down.
Minor infections can trigger sweating, such a the common cold.
But serious diseases, like human immunodeficiency virus (HIV) can also cause sweating, the NHS says.
HIV is a virus that damages the cells in your immune system and weakens your ability to fight everyday infections and disease.
According to sexual health charity, the Terrence Higgins Trust, night sweats in HIV are almost always accompanied by other symptoms, including fever, diarrhoea, weight loss, enlarged lymph nodes, and joint pain.
4. Cancer
Cancer, specifically Hodgkin’s and non-Hodgkin’s lymphoma can also lead to night sweats.
Both cancers begin in white blood cells, part of the body’s germ-fighting immune system.
However, night sweats are rarely the only symptom.
Both diseases show with a painless swelling in a lymph node, usually in the neck, armpit or groin.
5. High blood pressure
Night sweats can also be a sign of high blood pressure, otherwise known as hypertension, in those who suffer from obstructive sleep apnoea.
Sleep apnoea where the airway is repeatedly blocked during sleep and there is loud snoring.
Studies suggest around a third of people with the sleep condition regularly experience night sweats.
The exact reason behind the phenomena is unknown, but scientists believe it is linked to high blood pressure.
6. Medications
Certain medicines, such as selective serotonin reuptake inhibitors (SSRIs) which is used to treat depression and hormone replacement therapy for menopause, can cause sweating at night.
These drugs impact the part of the brain which is responsible for regulating body temperature and sweating.
Scientists have found abusing party drugs and alcohol can also also increase the risk of night sweats in the same way as prescribed drugs.