Sweating

Sweating is a normal way for your body to control its temperature. Sweat glands release fluid onto your skin. As the fluid evaporates, it helps cool you.

You may sweat during exercise, in hot weather, with a fever, or when you feel nervous. Hormonal changes, medicines, and health conditions can also affect how much you sweat.

Sweating that is heavier than your body needs for cooling is called hyperhidrosis. It may affect one area, such as the palms or armpits, or the whole body. Sweating itself is a symptom, not a diagnosis.

Your skin may feel warm, damp, or sticky. Sweat may form small beads, run down your skin, soak through clothing, or make shoes and socks wet.

Some patterns can help narrow down the cause:

• Focal sweating affects particular areas, often both palms, soles, armpits, or sides of the face
• Generalised sweating affects much of the body
• Night sweats soak sleepwear or bedding even though the room is comfortably cool
• Cold sweats cause cool, clammy skin and may occur with pain, nausea, fear, or illness

Heavy sweating can lead to skin irritation, body odour, cracked skin, or repeated fungal infections. It can also make writing, holding objects, wearing certain clothes, or taking part in social activities difficult.

Sweating commonly increases because your body needs to cool down. Warm weather, exercise, heavy clothing, hot drinks, or spicy food may trigger it.

Strong emotions can activate sweat glands, especially on the palms, soles, face, and armpits. Anxiety, embarrassment, pain, and stress are common triggers.

Hormonal changes can cause episodes of warmth and sweating. Hot flushes around menopause are one example. Pregnancy and menstrual changes can also affect sweating.

Some people have primary focal hyperhidrosis. This means excessive sweating occurs in specific areas without another illness causing it. It often affects both sides of the body and may run in families.

Less common causes include an overactive thyroid, low blood sugar, infections, sleep apnoea, and conditions affecting nerves or hormone levels. Alcohol and withdrawal from alcohol or certain drugs can also cause sweating.

Medicines may contribute, including some antidepressants like sertraline or fluoxetine, pain medicines, hormone treatments, and medicines that lower blood sugar. Do not stop a prescribed medicine without discussing it with the prescriber.

Call emergency services if sudden heavy sweating occurs with chest pressure or pain, severe breathing difficulty, fainting, marked weakness, or confusion. These symptoms may signal a serious heart or circulation problem.

Confusion, collapse, seizures, or very high body temperature during hot weather or exercise can indicate heatstroke. Move to a cooler place and seek emergency help. Do not wait for the person to stop sweating.

If you have diabetes, sweating with shaking, hunger, dizziness, or confusion may mean low blood sugar. Follow your personal low-blood-sugar plan. Seek emergency help if you cannot swallow safely, lose consciousness, or do not recover.

Arrange a routine medical appointment if sweating:

• Starts without a clear reason or becomes noticeably heavier
• Regularly wakes you or soaks your bedding
• Interferes with work, sleep, relationships, or everyday activities
• Occurs with ongoing fever, unexplained weight loss, a racing heartbeat, or persistent cough
• Began after starting or changing a medicine
• Causes repeated rashes, broken skin, or infections

A clinician will ask when the sweating began, where it occurs, and whether it happens during sleep. They may ask about triggers, fevers, weight changes, menstrual changes, medical conditions, and family history.

Bring a list of medicines, supplements, alcohol use, and recreational drugs. Note whether the sweating started after a medicine or dose change.

An examination may look for skin changes, fever, thyroid enlargement, or changes in heart rate. Tests are not always needed. Depending on your other symptoms, blood or urine tests may check blood sugar, thyroid function, infection, or other possible causes.

Keeping a short diary can help. Record when sweating happens, the body areas involved, possible triggers, medicines taken, and any symptoms occurring at the same time.

Treatment depends on whether the sweating is a normal response, primary hyperhidrosis, or a symptom of another condition. Treating an underlying cause or reviewing a contributing medicine may reduce it.

For everyday comfort, you can:

• Wear loose, breathable clothing and change damp clothes or socks
• Keep rooms cool and drink enough fluid during heat or exercise
• Notice whether spicy foods, alcohol, caffeine, or stress trigger episodes
• Dry skin folds carefully and treat irritated skin early
• Choose an antiperspirant rather than deodorant when reducing wetness is the goal

Antiperspirants reduce sweat reaching the skin. Deodorants mainly reduce odour. Stronger antiperspirants can irritate skin, so follow the product directions and avoid applying them to broken or freshly shaved skin.

For persistent hyperhidrosis, a clinician may discuss prescription antiperspirants, medicated creams or wipes, or iontophoresis. Iontophoresis uses a mild electrical current through water, usually for hands or feet. Botulinum toxin injections can temporarily reduce sweating in selected areas.

Medicines that reduce sweating throughout the body are sometimes used, but side effects can limit them. Procedures involving sweat glands or nerves are usually reserved for severe symptoms that have not improved with other treatments.

Sweating caused by heat, exercise, stress, or a short illness usually eases when the trigger passes. Hormone-related sweating may come and go over time.

Primary focal hyperhidrosis can be long-lasting, but treatments may reduce its effect on daily life. More than one approach may be needed.

Sweating caused by a medicine or health condition may improve when the cause is addressed. Follow-up is important if the pattern changes, treatment is not helping, or new symptoms appear.

Are night sweats always a sign of illness?

No. A warm room, heavy bedding, menopause, stress, alcohol, and some medicines can cause night sweating. Book an appointment if it repeatedly soaks your clothes or bedding, especially with fever, weight loss, cough, or other unexplained symptoms.

Why do my palms sweat when I am nervous?

Nervousness activates the body’s stress response. This can stimulate sweat glands in the palms, soles, face, and armpits even when you are not hot.

Does body odour mean I am sweating too much?

Not necessarily. Sweat itself is usually nearly odourless. Odour develops when skin bacteria break down parts of sweat. Washing, drying the skin, changing damp clothes, and using deodorant may help.

Can sweating cause dehydration?

Heavy or prolonged sweating can lead to fluid loss, especially during heat or exercise. Thirst, dark urine, dizziness, and reduced urination can be signs that you need fluids and a cooler environment.