Quick version
Excessive sweating (hyperhidrosis) is divided into two types: primary, which is a harmless condition often localized to the hands, feet or armpits, and secondary, where the sweating is caused by drug side effects or diseases such as thyroid disorders and menopausal symptoms. Night sweats or a sudden change should be investigated in healthcare, and if the sweating occurs together with chest pain or dizziness, emergency help is required. However, there is effective help available, from strong antiperspirants to prescription treatment and Botox.
There are days when sweating feels completely reasonable: at the gym, in the heat of summer or during a stressful presentation. But what if your shirt gets wet on the way to the bus, your hands are slippery when shaking hands or you wake up sweaty without the bedroom being warm.
Why do I sweat so much? Common causes, warning signs and what you can do
Sweating is the body's way of regulating temperature. When sweating becomes more pronounced than the situation requires, it is called hyperhidrosis, or excessive sweating. It can be a harmless but bothersome condition, but sometimes sweating is a signal that something else in the body needs to be investigated.
When is a lot of sweating normal – and when does it count as hyperhidrosis?
Everyone sweats differently. Genetics, body size, fitness, hormones, temperature and stress affect how much you sweat. Getting sweaty during exercise, fever, spicy food or heat is therefore normal.
Hyperhidrosis means that you sweat more than your body needs to cool itself. It can be noticeable as dripping armpits, wet palms, damp soles of your feet or sweaty clothes despite calm activity. For some, it happens at least once a week and affects work, sleep, social life or self-confidence.
Doctors usually distinguish between two main types. Primary hyperhidrosis is a separate condition in which the sweat glands are overactivated by nerve signals without finding any other disease as an explanation. Secondary hyperhidrosis means that the sweating is instead due to another medical cause or a side effect of medication.
Why do I sweat so much from my hands, feet or armpits?
If you mainly sweat from your hands, feet, armpits or sometimes your face and scalp, it is often primary hyperhidrosis. It typically begins in childhood or adolescence, is often symmetrical on both sides of the body, and does not usually cause excessive sweating when you sleep.
This does not mean that you are “sweating because you are nervous,” although stress often worsens the symptoms. In people with primary hyperhidrosis, the nerve signals to the eccrine sweat glands appear to be overactive. Eccrine sweat glands are the sweat glands that primarily regulate the body’s temperature.
In everyday life, primary hyperhidrosis can be noticeable in quite tangible ways. You may avoid light-colored shirts, change socks in the middle of the day, have difficulty holding paper or a cell phone, or hesitate to shake someone’s hand. The symptoms are rarely dangerous in themselves, but they can significantly affect the quality of life.
What diseases or medications can cause you to sweat a lot?
If you have suddenly started sweating more than before, if you sweat over large parts of your body or if the sweating occurs at night, you need to think more broadly. Secondary hyperhidrosis can be due to hormonal conditions such as overactive thyroid, low blood sugar, diabetes, menopausal symptoms or more unusual conditions with increased stress hormone influence. Infections, neurological diseases and certain cancers can also cause increased sweating.
Medications are a common but often overlooked cause. Examples include certain antidepressants, antipsychotics, insulin, painkillers, steroids and some hormone treatments. If the sweating started after you started a new medication, that is an important clue.
For women in their 40s and 50s, hot flashes and sweating are common during perimenopause and menopause. Then the sweating often comes in attacks with a sudden feeling of heat in the face, neck and chest, sometimes accompanied by palpitations or anxiety.
Night sweats have a slightly different meaning than daytime sweating. Getting hot under a thick blanket is normal, but recurring night sweats with wet bedding in a cool room should be evaluated, especially if they are combined with weight loss, fever or other general symptoms.
More than just hot? How to know if your sweating requires treatment
You should seek medical attention if the sweating has started suddenly, is getting noticeably worse or is interfering with everyday life for a longer period of time. This also applies if you regularly sweat at night, if self-care does not help or if you are also taking medication that can cause sweating as a side effect.
Some symptoms require a faster assessment. Heavy sweating together with chest pain, dizziness, cold skin or a rapid pulse can be signs of an acute condition. Also seek medical attention if the sweating is accompanied by involuntary weight loss, prolonged fever, cough, diarrhoea or a pronounced feeling of illness.
When you see a doctor, your doctor will usually try to determine whether you have primary or secondary hyperhidrosis. The pattern then plays a big role: where on your body you sweat, when it started, whether it is hereditary, whether you sweat during sleep and what medications you are taking. Sometimes blood or urine tests are needed to look for underlying causes, such as thyroid disorder or blood sugar problems.
What can be done about excessive sweating?
Treatment depends on the cause. If the sweating is due to another illness or medication, the most important thing is to treat the root cause or review the medication together with your healthcare provider.
In primary hyperhidrosis, it often starts simply. Strong antiperspirants with aluminum salts are the first-line treatment for many, especially for the armpits but also sometimes for the hands and feet. They work differently than deodorant: they reduce the amount of sweat itself instead of just masking the odor.
If that's not enough, there are more options. For hands and feet, iontophoresis can be used, which means that the skin is treated with a weak electric current in a water bath. Botulinum toxin can reduce sweating in the armpits, palms of the hands, soles of the feet and sometimes the face by blocking the nerve signals to the sweat glands for a period.
In more severe cases, tablets with an anticholinergic effect may be used. They reduce the stimulation of the sweat glands but can cause side effects such as dry mouth, constipation, blurred vision and poor heat tolerance, which means that the treatment needs to be carefully weighed against the benefits. Surgery is rarely used and mainly when other treatments have not helped.
There are also simple measures that can make everyday life easier, even if they do not solve the underlying problem:
- use antiperspirant in the evening so that it has time to work in peace and quiet
- choose airy clothes and materials that breathe
- change socks often if your feet sweat and wear shoes that have time to dry between uses
- try to identify triggers such as spicy food, alcohol, stress or hot environments
- protect your skin if sweating causes chafing, eczema or foot problems
If you suspect that stress is playing a role, it can be helpful to observe the pattern rather than blaming yourself. Sweating can be exacerbated by anxiety, but the problem may also be an underlying medical condition. This distinction is important, as it affects which treatments actually work.
Excessive sweating can easily fall into the “annoying but not serious” category, which is why many people wait a long time to seek help. But when the symptom changes, becomes generalized, or comes along with other bodily signals, it can provide valuable information about metabolism, hormones, and blood sugar—things that aren’t visible on the outside.
