While sweating is a normal immune response to infection, it’s important to check out any persistent issues with your GP Image Credit: Getty Images/Fuse

As the temperature finally starts to climb, many of us may be feeling hot under the collar. But though sweating is normal — it keeps the body cool — excess perspiration may be a sign of a health issue.

Sweating is a normal immune response to infection, as the body pushes up its temperature to try to kill off the germ or virus. But it’s important to check out any persistent issues with your GP.

Here, we look at the causes of sweating and what you can do about them.

Sweating can be a sign of hypoglycaemia — a drop in your blood sugar levels. Though this is usually associated with diabetes, it can happen to non-diabetics when they have missed a meal, says Dr Stephen Lawrence, a GP and medical adviser for Diabetes United Kingdom.

The body produces the hormone insulin in expectation of food at mealtimes — the hormone is needed to regulate the amount of glucose that gets into our blood from food.

When we skip a meal, the lack of glucose in the blood triggers the release of adrenaline because the body goes into “fight or flight” survival mode — this causes the sweating. Other symptoms of low blood sugar can include hunger pangs and palpitations.

To get an instant spike in blood sugar, have a handful of soft, sugary sweets such as jelly beans. You should then have a meal to keep levels steady and avoid a drop in blood sugar.

Avoid the temptation to have a bar of chocolate — the fat in sweet products reduces the absorption of glucose by the body’s cells, so it will take longer for you to feel better.

Constant sweating can be a sign of an overactive thyroid or hyperthyroidism. The thyroid gland produces a hormone that controls how quickly the body uses its energy stores as well as its sensitivity to other hormones. When too much thyroid hormone is produced, this can cause constant sweating (by stimulating the sweat glands).

Hyperthyroidism can also lead to weight loss and palpitations, says Dr Mark Vanderpump, consultant endocrinologist at the Royal Free Hospital, London.


Medication can be used to bring down hormone levels, says Dr Vanderpump.

However, this can take around a month to have an effect. So drugs known as beta-blockers are also given, as these have a more immediate effect on palpitations and increased heart rate. They work by blocking the release of the hormones, adrenaline and noradrenaline.

Men who sweat at night, even when it isn’t particularly warm, could have low testosterone levels, says Christopher Eden, consultant urologist at the Royal Surrey County Hospital.

When testosterone levels are low, the hypothalamus — an area in the brain that regulates many functions including body temperature and blood pressure — receives false signals that the body is overheated; sweating is the body’s way of cooling down.

Testosterone is also needed for muscle strength and bone density, so those with low levels may feel weak and unusually lethargic.

A major cause of low testosterone is having mumps as a child because it can cause inflammation and testicular damage.

Night sweats in women are a sign of the menopause, says Leila Hannah, consultant gynaecologist at Queen Mary’s Hospital, Sidcup — though it’s not known why lowering levels of oestrogen has this effect, especially at night.

Sweating may be worse just before or during the menstrual cycle because this is when oestrogen levels are at their lowest.

Low testosterone in men can be diagnosed by a blood test and treated with testosterone supplements in the form of gels or injections.

However, before treatment, it is vital your GP gives you a prostate-specific antigen (PSA) test to ensure there’s no sign of prostate cancer. Testosterone can drive progress of this disease.

Alternative natural remedies, such as red clover, have been found to help menopausal sweating in 60 per cent of women. The herb is rich in plant chemicals known as phytoestrogens, which mimic oestrogen. If natural remedies don’t help, discuss hormone replacement therapy with your GP.

Night sweats are often made worse by consuming alcohol.

Sweating can be a side-effect of antidepressants — this is because they can increase levels of stress hormones such as noradrenaline, leading to excess perspiration, says Dr Declan Leahy, consultant psychiatrist at the Private Psychiatry clinic in Kent.

This can happen at any time — though many people taking these drugs experience night sweats.

Other medications that cause sweating include blood pressure medications, medicines for dry mouth, cold and flu remedies that contain pseudo-ephedrine, iron tablets and antibiotics. Ceasing intake of strong painkillers can sometimes cause sweating, too.

For those suffering from depression, relaxation or exercise are stress-busters. Caffeine boosts blood pressure and increases heart rate, so it may exacerbate sweating.

Most people produce a litre of sweat each day, even more when it’s hot or while exercising. If you find yourself sweating even when the weather is cold or there are no triggers, it could be a sign of hyperhidrosis.

It causes them to produce up to ten times as much sweat. They feel constantly damp though it can get even worse with heat, exercise or anxiety.

Those who suffer with hyperhidrosis are thought to have an excessive number of nerve signals travelling from the brain to the sweat glands, says Dr Sajjad Rajpar, consultant dermatologist at the Queen Elizabeth Hospital in Birmingham.

Using an anti-perspirant that contains aluminium chloride, such as Driclor, can help, as it blocks the sweat glands. However, it can cause irritation.

Botox injections in the palms can give some relief, by blocking nerve impulses that control the sweat glands. The effects usually wear off after six to nine months.

Another treatment — iontophoresis — involves placing the affected area in water that has a gentle electrical current running through it for 20 to 30 minutes. This slows down secretion of the sweat glands.

Patients usually need two to four sessions a week. Symptoms should begin to improve after a week, after which it may be necessary to go only once a month. Iontophoresis is effective in 80 to 90 per cent of cases.

As a last resort, there is surgery to sever the nerves that control the sweat glands. However, this can lead to increased sweating elsewhere, as the accumulated sweat is secreted through other sweat glands. As with all operations, there is a risk of infection.

Sweating and feeling faint can be a warning sign of a heart attack. There may be chest pains first or the symptoms may come on after exercise.

Other symptoms include squeezing, heavy chest pain that can radiate from the chest to the jaw, neck, arms and back.

This kind of sweating is part of the vasovagal response, which causes a sudden drop in heart rate and blood pressure, says Dr Charles Knight, a consultant cardiologist at Barts and the London NHS Trust.

This vasovagal response can also occur if someone is in severe pain, suffering from a brain bleed (which would also cause an extremely bad headache) or acute appendicitis (which causes tenderness and sharp pain in the lower right-hand abdomen).

Anyone having a suspected heart attack needs to get to hospital quickly. While they are waiting for the ambulance, they should sit in a comfortable position and, unless allergic, slowly chew a 300mg aspirin.

This will help to thin the blood, reduce blood clots and can help to prevent the clot that is blocking the artery from spreading.

— Daily Mail