Excessive Sweating: Why Am I Sweating So Much?

How much sweating is too much?

Sweating cools the body and increases with heat, exercise, fever, stress and spicy food. Doctors call it excessive when it is out of proportion to these triggers and causes problems such as:

• soaked shirts or visible sweat patches within minutes
• dripping palms that make it hard to write, shake hands or use a phone
• skin softening, cracking or infections from constant moisture
• avoiding social situations or changing clothes several times a day

Primary vs secondary sweating

Primary hyperhidrosis is common, affecting a few percent of people. It is explained in detail on the hyperhidrosis page.

Causes of excessive sweating

Hormonal changes

• Menopause and perimenopause: hot flashes and night sweats affect most women around menopause and can last several years.
• Pregnancy: hormonal changes increase sweating.
• Low testosterone in men, including during prostate cancer treatment.

Overactive thyroid

Hyperthyroidism speeds up metabolism, causing heat intolerance, sweating, a fast heartbeat, tremor, weight loss and anxiety. A blood test confirms it.

Low blood sugar

Hypoglycemia, mostly in people taking insulin or some diabetes tablets, causes sudden sweating, shakiness, hunger, a fast heartbeat and confusion. Eating or drinking 15 g of fast-acting sugar treats it.

Anxiety and panic

Anxiety triggers sweating through adrenaline, often on the palms, armpits and face. Panic attacks cause sudden sweating with a pounding heart, breathlessness and fear.

Medicines and substances

• Antidepressants, especially SSRIs, SNRIs and tricyclics
• Opioids, and withdrawal from opioids or alcohol
• Diabetes medicines (via low blood sugar)
• Hormone treatments, some blood pressure medicines and fever reducers
• Caffeine, nicotine and alcohol

Infections

Fever from any infection causes sweating as the temperature falls. Long-lasting night sweats can signal tuberculosis, HIV or endocarditis.

Other causes

• Obesity: more heat to dissipate and more insulation.
• Heart attack: sudden cold sweat with chest discomfort is a warning sign.
• Lymphoma and other cancers: drenching night sweats with fever and weight loss.
• Pheochromocytoma and carcinoid syndrome: rare hormone-producing tumors that cause episodes of sweating, flushing, headache and racing heart.
• Nerve problems: diabetic neuropathy, spinal cord injury or Parkinson's disease can cause abnormal sweating patterns, such as heavy sweating on the upper body with little below.
• Gustatory sweating: sweating on the cheek while eating, after parotid gland surgery or in diabetes (Frey syndrome).

Excessive sweating at night

Sweating at night because the room is too warm or the bedding too heavy is common. True night sweats soak your nightclothes and sheets despite a cool room. Common causes are menopause, medicines, anxiety and reflux. Night sweats with fever, weight loss or swollen glands need assessment for infection or lymphoma.

How doctors assess excessive sweating

A doctor will ask when it started, where it happens, whether it occurs during sleep, family history, medicines, menstrual changes, weight changes and other symptoms. Tests for secondary causes may include:

• blood sugar and HbA1c
• thyroid function tests
• a blood count and inflammation markers
• tests for infections such as tuberculosis or HIV if night sweats and other symptoms suggest them
• a chest X-ray when indicated

Specialists may use a starch-iodine test to map sweating areas before treatment.

Treatment for excessive sweating

Treat the cause

Adjusting a medicine, treating thyroid disease, managing menopause symptoms or treating an infection often resolves secondary sweating.

Treatments for primary hyperhidrosis

1. Clinical-strength antiperspirants containing aluminum chloride or aluminum salts, applied at night to dry skin.
2. Topical prescription treatments, such as anticholinergic wipes or gels for the armpits.
3. Iontophoresis: soaking hands or feet in water carrying a mild electrical current, several times a week. Effective for palms and soles.
4. Botulinum toxin injections: block the nerves that trigger sweating for about 4 to 12 months.
5. Oral anticholinergic medicines: reduce sweating all over but can cause dry mouth and blurred vision.
6. Microwave treatment for the armpits, or surgery (sympathectomy) for severe cases, which carries a risk of compensatory sweating elsewhere.

Everyday measures

• Wear loose, breathable cotton or moisture-wicking fabrics.
• Change socks often and use absorbent foot powder.
• Carry spare shirts and use underarm shields.
• Limit caffeine, alcohol and spicy foods if they trigger sweating.

Frequently asked questions

Why am I suddenly sweating so much?

Sudden new sweating can come from menopause, a new medicine, anxiety, fever, low blood sugar, an overactive thyroid or alcohol withdrawal. A cold sweat with chest pain or breathlessness could be a heart attack and needs emergency care. Persistent new sweating deserves a medical check.

Is excessive sweating a sign of a serious illness?

Usually not. Most excessive sweating is primary hyperhidrosis or due to heat, menopause, anxiety or medicines. It is more concerning when it is new, all over the body, happens at night, or comes with fever, weight loss, chest pain or a racing heart.

What causes cold sweats?

Cold sweats happen when the stress response triggers sweating while skin blood vessels narrow. Causes include pain, panic attacks, low blood sugar, shock, severe infection and heart attack. Cold sweats with chest discomfort, breathlessness or fainting need emergency care.

Can anxiety cause excessive sweating?

Yes. Anxiety releases adrenaline, which stimulates sweat glands, especially on the palms, armpits and face. Worry about sweating can then make it worse. Treating anxiety and using antiperspirants or hyperhidrosis treatments often helps.

What is the best treatment for excessive sweating?

For primary hyperhidrosis, start with a clinical-strength antiperspirant. If that fails, options include prescription topical treatments, iontophoresis for hands and feet, botulinum toxin injections and oral medicines. For secondary sweating, treating the underlying cause works best.