Sweat, or perspiration, is your body’s way of cooling down. You may therefore sweat when you are exercising or feeling too hot eg in warm weather or when you are feeling afraid, angry or stressed.

Excessive sweating refers to sweating when your body does not need to cool down. It is a common complaint, which often starts when you are a child or teenager and can cause social anxiety and embarrassment.

Sometimes symptoms improve with age. It can usually be effectively treated and you should therefore speak to your GP if you are concerned about excessive sweating.

Excessive sweating causes

Your armpits, feet, hands, face, groin or scalp are most likely to be affected by excessive sweating. Excess sweat in these areas of your body most often happens for no particular reason. However, it can be triggered by certain foods, drinks and stressful situations.

Sometimes, frequent and excessive sweating all over your body can be a symptom of:

A side effect of certain medications or supplements — this includes:

Certain antidepressants eg desipramine, nortriptyline and protriptyline
Medication for dry mouth, specifically pilocarpine
Zinc as a dietary supplement

Anxiety or stress
Substance or alcohol abuse or withdrawal

Less commonly it can be caused by:

A serious illness, such as tuberculosis or malaria
Cardiovascular, spinal or respiratory problems
Hyperthyroidism
Menopause
Some cancers

Types of excessive sweating

Primary (idiopathic) focal hyperhidrosis

This causes excessive feet sweating, excessive underarm sweating and excessive palm sweating. It affects both armpits, feet and hands on both sides of your body while the rest of your body sweats normally. It is not associated with any other conditions and the cause is unknown. Although it can develop at any age, it usually develops before age 25. It affects both men and women equally and occurs in around three in every 100 people.

Primary focal hyperhidrosis can come and go and vary in severity. Certain triggers can worsen it, including anxiety, heat, spicy foods and strong emotions.

Gustatory sweating is a type of focal hyperhidrosis triggered by eating and usually occurs on your face, forehead, neck and scalp.

Secondary focal hyperhidrosis

This refers to excessive sweating on one particular part of your body and is rare. There is usually a known cause eg spinal disease or injury causing excessive sweating in one leg. You may need tests to diagnose the underlying cause.

Generalised hyperhidrosis

This refers to excessive sweating all over your body and is not as common as primary focal hyperhidrosis. It usually has a known cause, such as anxiety or side effects caused by certain medications. Other health conditions that can cause generalised hyperhidrosis, include:

Certain cancers
Infections and infectious diseases — this includes HIV and tuberculosis
Menopause
Problems affecting your respiratory or cardiovascular system — this includes heart problems, lung disease and stroke
Problems affecting your hormones — this includes adrenal gland disorders and hyperthyroidism
Problems affecting your nervous system — this includes spinal nerve damage and Parkinson's disease

Complications of excessive sweating

Excessive sweating is not a serious health condition but can make you feel embarrassed and anxious, especially in social situations or when doing sports. It can cause complications in your everyday life eg:

Armpit sweating causing sweat patches on your clothes under your arms
Excessive sweating on any part of your body being soaked up by your clothes so you have to change your clothes in the middle of the day
Sweaty hands leaving sweat marks on documents and keyboards or having a sweaty handshake

Getting a diagnosis for excessive sweating

If you have been sweating excessively and frequently, ie at least once a week for six months or more, see your GP. You should also see your GP if:

Excessive sweating is making your normal life difficult
You are having regular night sweats
You are taking medication that can cause excessive sweating
Your family has a history of excessive sweating

You should see your GP urgently if your excessive sweating is persistent and occurs for no apparent reason or if it occurs:

Alongside a fever, chest pain, breathlessness and rapid heartbeat
Alongside chest pain or a feeling of pressure on your chest — these are signs of a possible heart attack
Alongside unintentional weight loss
While you sleep

Your GP will discuss your sweating and suggest ways to control excessive sweat. They will ask you about your symptoms, general health and any family history of excessive sweating, and may perform a physical examination — this is usually enough to diagnose primary focal hyperhidrosis. They may also need to arrange tests to check for any underlying causes for your sweating. Tests include:

Blood tests
Paper test — this involves placing a special type of paper on the sweaty area of your body
Starch-iodine test — this involves placing iodine on the sweaty area of your body
Thermoregulatory test
Urine test

Your GP may refer you to a consultant dermatologist, a doctor who specialises in treating skin conditions, for further assessment, diagnosis and treatment.

Excessive sweating treatments

Although there is no one quick fix for excessive sweating, there are several ways you can help reduce or prevent excessive sweating, such as:

Adjusting your wardrobe

Alternating the pairs of shoes you wear every other day so each pair can fully dry out
Avoiding tight clothes and man-made fabrics — choose loose-fitting outfits made from natural materials such as cotton and silk
Changing your socks at least twice a day
Wearing black or white clothes as sweat marks don’t show up as obviously on these colours
Wearing armpit or sweat shields to protect your clothing from absorbing your sweat
Wearing moisture-absorbing socks and, rather than trainers or boots, choosing leather shoes

Avoiding triggers for your sweat

Triggers may include alcohol, spicy foods, caffeine, chocolate or simply the anxiety of being in a large group of people.

Changing your personal hygiene products and routine

Dusting sweaty feet with foot powders
Using an antiperspirant — apply to the affected areas (eg armpits, palms and soles of your feet) at night and wash off in the morning; if your skin becomes irritated or inflamed stop using the antiperspirant
Using antiperspirants regularly instead of deodorants — antiperspirants reduce sweat release while deodorants simply cover up the smell of sweat
Using soap substitutes that are gentler on your skin

If these suggestions don’t reduce your excessive sweating, your GP or consultant may recommend other medical or surgical treatments. The treatment you receive will depend on your symptoms and any underlying condition causing your excessive sweating. This may include:

Medication

If you have excessive sweating after eating or drinking, you may be prescribed propantheline tablets.

Botulinum toxin injections

If you have excessive armpit sweating, your doctor may recommend botulinum toxin injections into your armpits just under the skin. Botulinum toxin stops the nerves that control your sweat glands from working. The effect wears off after four to 12 months.

This treatment cannot be used to treat excessive face or palm sweating.

Iontophoresis

If you have excessive sweating in your armpits, palms or soles of your feet, your doctor may recommend iontophoresis. This involves placing the affected areas of your body into a small container filled with water. A weak electric current is passed through the water using a special machine.

The treatment is safe and doesn't cause pain although you may experience some discomfort and/or a 'pins and needles' sensation. You will need a series of treatments, usually six to 10 sessions spread over two or three weeks. Each session takes around 20-40 minutes.

This treatment doesn't always work and side effects include dizziness and a dry or sore mouth and throat for up to 24 hours after each session.

Surgery to remove small sections of your sweat glands

Surgery for excessive armpit sweating

There are several surgical techniques to remove the sweat glands from your armpits, including:

Laser sweat ablation — this involves using laser energy to destroy your sweat glands; it may cause less scarring than other surgical techniques
Suction curettage — this involves making a small cut in your skin and removing the sweat glands through this cut

Surgery for excessive palm sweating

Surgery called endoscopic thoracoscopic sympathectomy can be performed to cut out some of the nerves controlling the sweat glands in your hands, which run down the side of your spinal cord. This is a keyhole surgery, which means it uses small cuts and involves passing a thin telescope-like tube into your body to find the nerve before cutting it out.

A known complication of this surgery is an increase in sweating in other parts of your body eg chest or groin.

Frequently asked questions

What deficiency causes excessive sweating?

Excessive sweating is not caused by a deficiency in any vitamin or mineral. However, excessive sweating can cause you to become deficient in certain minerals and salts, such as sodium, as you lose them through your sweat.

Is excessive sweating a sign of diabetes?

Excessive sweating can be a symptom of a complication that occurs as a result of poorly controlled diabetes called autonomic neuropathy. This refers to damage to your nerves and can affect the nerves that control sweating. If you have autonomic neuropathy, you are more likely to experience gustatory hyperhidrosis ie excessive sweating soon after eating or drinking.

You may also have night sweats if you have diabetes and your blood sugar levels drop too low overnight while you are sleeping. This most commonly occurs in people with diabetes who are being treated with insulin or sulfonylurea tablets.

Why do I sweat so easily when exercising?

Some people are more prone to excessive sweating when exercising although the reasons are unclear. Sometimes excessive sweating runs in families. It is usually not something to worry about unless it is causing you anxiety, embarrassment or preventing you from carrying out your normal activities.

Does high blood pressure cause sweating?

High blood pressure doesn’t usually cause sweating. However, a rare tumour called pheochromocytoma can cause both high blood pressure and sweating.

Should I wipe my sweat during exercise?

Sweating helps you cool down, so if you want to feel cooler, do not wipe your sweat off. Instead, let your sweat evaporate off your body, which will cool you down. However, if you are drenched in sweat and it is getting in your eyes or otherwise making it difficult to continue with your exercise, you can wipe it off.

Does sweating help lose weight?

Sweating does not help you lose excess fat but can temporarily help you lose a little weight due to the loss of fluids from your body.