Five reasons you may be sweating a lot

Sweating is your body’s way of cooling down. You may sweat after exercise or when the weather is warm as your body works to regulate its temperature. You may also find that you sweat when you’re feeling angry or stressed. 

What is excessive sweating?

While some sweating is normal, some people suffer from excessive sweating. This is when you sweat when your body doesn’t need to cool down. Excessive sweating is fairly common and usually starts in childhood or during your teenage years. 

Typically, your face, armpits, groin, feet, hands or scalp are most likely to experience excessive sweating. These areas of your body can experience excessive sweating for no reason, although it can also be triggered by stress or certain foods or drinks. 

How much sweat is too much?

The average person will sweat anywhere between 500ml and 700ml during regular activity on a day-to-day basis. This might increase if the weather is particularly hot or if you’re more active than usual. 

As you can’t easily measure how much you’re sweating, it can be hard to say exactly how much sweat is too much. However, you may be sweating an excessive amount if you:

• Are self-conscious about how much you sweat
• Need to deal with sweat a lot during the day eg need to change your clothes or wash a lot
• Often sweat through your clothes
• Tend to be prone to skin infections

You’re also at greater risk of excessive sweating if other members of your family sweat excessively. 

So what causes excessive sweating and how can it be treated? 

1. Primary focal hyperhidrosis

One of the most common causes of excessive sweating, primary focal hyperhidrosis, isn’t a sign of a serious illness. This condition usually manifests as symmetrical excessive sweating, meaning that it will happen on both sides of your body eg both hands. It most commonly causes excessive sweating under the arms.

It isn’t clear what causes primary focal hyperhidrosis but it’s thought to be a problem in the nervous system that’s passed on genetically. It causes the body to produce sweat when it isn’t needed to cool you down.

2. Thyroid issues

The thyroid is a gland in your neck that produces thyroid hormones. These hormones are vital to a range of processes that occur in your body, including controlling your energy levels, internal temperature, metabolism, weight, and skin, hair and nail growth. 

If you have an underactive thyroid, it’s more likely that you will be sensitive to heat and experience excessive sweating. This is made worse by the fact that an underactive thyroid is more likely to result in you being overweight or obese, which can make you more prone to feeling hotter. 

If you experience symptoms of a thyroid disorder or have a family history of thyroid problems, it is important to get your thyroid checked via blood tests. Your doctor will then let you know whether you need treatment for an underactive thyroid, which will consequently address your excessive sweating if this is the underlying cause.

3. Diabetes

If you have diabetes, you may experience excessive sweating in a few different situations:

• When you are sleeping
• When you eat certain foods
• When you have low blood sugar

Low blood sugar is the most common cause of excessive sweating due to diabetes. When your blood sugar levels drop too low, it causes your body to produce more adrenaline, which then causes sweating. This can happen during the day but can also cause night sweats when you have diabetes. 

Controlling your blood sugar levels if you’re diabetic will help you control any excessive sweating. When it comes to night sweats, altering your diet, and when you eat and exercise can help reduce these by better regulating your blood sugar levels while you sleep.

4. Medication

Certain medications can cause excessive sweating. If you’ve been prescribed a new medication and suddenly have started sweating more than usual, this may be the cause.

Certain antidepressants (eg selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants), opioid painkillers and cholinesterase inhibitors, which are used to treat dementia, can all cause excessive sweating.

If you think that your medication could be the cause of your excessive sweating and you’re finding it uncomfortable, talk to your GP.

5. Changing hormone levels

Changes in your hormone levels can trigger excessive sweating. In women, hormone changes are experienced during pregnancy and during perimenopause, which occurs before the body goes through menopause.

Changes in oestrogen levels affect how your body controls its temperature, which can lead to hot flushes and excessive sweating as your body works hard to cool you down.

Hormone changes caused by pregnancy will balance out after birth and you should see your sweat levels return to normal.

For sweating caused by perimenopause, wear cool and comfortable clothing, and keep your bedroom cool at night to help reduce how much you sweat.

How is excessive sweating diagnosed and treated?

If you’ve been experiencing excessive sweating for at least six months, nothing you’ve tried has helped and it’s affecting your daily activities and wellbeing, talk to your GP. 

If your sweating is caused by a medication, your GP may suggest an alternative. If diabetes is the culprit, they can discuss various techniques to better manage your blood sugar levels to avoid them getting low enough to cause sweating. 

If your heavy sweating is not caused by a medication or pre-existing condition, your GP may refer you for tests to assess what is causing it and find the right treatment. These include:

• Anti-sweating injections — this temporary solution lasts six to 12 months and involves injecting medication to stop the signal from your brain that tells your body to sweat from reaching your sweat glands
• Surgery called a sympathectomy — this involves removing a small amount of nervous tissue that makes up a structure called your sympathetic nerve chain