All you need to know about sweat - plus 6 common problems

Want to avoid sweating?

With summer in full swing, there’s nothing like a spell of sunshine and warm weather to brighten the mood. A lucky few might even be finally jetting off on that long-awaited summer holiday, ready to bask in balmy temperatures we don’t often see here in the UK.

But whether you’re home or away this summer, it’s hard to avoid that one thing we’d all rather be without - sweat. Be it a pet peeve or a major problem, perspiration will bother most of us in one way or another when the weather is hot and sticky.

Don’t sweat it! We’re here with everything you need to know about common sweat problems and how to prevent, treat or avoid sweating problems completely.

Why do we sweat?

With sweat being the nuisance it is, wouldn’t it be great if humans had evolved to just stop sweating completely? Well, unfortunately not, despite how badly it can stink!

Sweat - or perspiration - is actually an extremely important bodily function and we’d be in trouble without it.

Our body temperature should stay at around 37 degrees to avoid hypothermia (when we’re too cold) and hyperthermia (you guessed it - when we’re too hot).

As your body’s internal temperature starts to rise due to hot weather or physical activity, a small region in the brain called the hypothalamus sends a message to the sweat glands all over your body telling them that you need to cool down.

These glands respond by producing sweat, for which you use the energy from excess body heat to convert into vapour that will then evaporate off your skin.

How to manage common sweat problems

Sure, sweating is really important for our bodies, but that doesn’t stop it from being really bothersome too. Perspiration problems are common and they aren’t something you need to be embarrassed about.

Managing these problems can be so easy that you won’t even need to break a sweat!


Hyperhidrosis is another name for excessive sweating. Idiopathic hyperhidrosis is the most common form - this means that there’s no underlying cause and it can affect absolutely anyone.

Some other possible causes of excessive sweating can include:

  • Obesity
  • Hormonal changes associated with the menopause
  • Illnesses associated with fever
  • Hyperthyroidism
  • Diabetes
  • Certain medications

Wearing loose, light clothing and avoiding possible triggers like alcohol or spicy foods can help if you’re experiencing excessive sweating. Try a pair of socks that are designed to absorb moisture and change them at least twice a day.

Avoid tight or synthetic fabrics like nylon and consider opting for leather shoes, changing them day to day.

You could also try an over-the-counter antiperspirant designed especially for hyperhidrosis, or a foot spray if your feet are particularly affected.

If you’re still struggling with excessive sweating after taking these steps, speak to your GP for expert advice.

Night sweats

Most people sweat during the night, but if you find yourself waking up with soaking wet clothes or sheets then it’s likely you’re having night sweats. You should see your GP if you notice any of the following:

  • You have night sweats regularly that wake you up or worry you
  • You have a very high temperature (or feel hot and shivery), a cough or diarrhoea
  • You have night sweats and are losing weight for no reason

Night sweats can be caused by a range of issues including menopause, anxiety, certain medicines, low blood sugar, alcohol or drug use and hyperhidrosis. If you’re struggling with night sweats, consider limiting your consumption of alcohol, tobacco, caffeine or illegal drugs.

Keep your bedroom at a comfortable temperature - read our guide on how to fall asleep when it’s too hot for some top tips on how to keep cool.

Don’t exercise, drink warm drinks or eat spicy foods before bed as these could have you sweating even more.


Chafing is a very common problem caused by friction and moisture where rubbing skin causes pain or a mild rash - sometimes even swelling or bleeding can occur. It occurs in places where your body parts rub against each other (like your thighs) or your clothing.

It’s common in people who are overweight and athletes who take part in endurance sports like cycling or running. If you’ve ever worn a skirt or a dress on a hot and humid day, you’ve likely experienced the annoyance of thigh chafing even if you aren’t overweight.

For thigh chafing in particular, wearing a pair of shorts underneath your skirt or dress can help to prevent your skin from rubbing together.

To prevent chafing in general, you can try applying antiperspirant or lotion to the affected area - look out for anti-chafing products that are designed to repel moisture and prevent friction.


If you’ve been exercising, out in the heat all day or suffer from hyperhidrosis, you could be at risk of becoming dehydrated.

That’s because your body will be losing a lot of water through sweating, so you’ll need to keep on top of your hydration. The signs of dehydration are:

  • Feeling thirsty
  • Dark or strong-smelling urine
  • Feeling dizzy or lightheaded
  • Feeling tired
  • Dry mouth, lips and eyes
  • Urinating fewer than four times a day

To prevent dehydration, simply make sure you’re drinking enough fluids - the recommended amount is around 8 glasses of water a day. You could also try a hydration multiplier to help your body absorb more water than through drinking alone.


Have you found that your skin seems to break out in spots during periods of hot weather or perhaps after an intense workout?

Sweat and heat can clog your pores and cause acne to appear, especially if you’ve been wearing tight clothing, headbands, hats or backpack straps that cause extra friction.

To try and prevent these types of spots on your body, make sure to shower with an antibacterial soap straight after a period of heavy sweating and wash your face twice a day with a gentle non-comedogenic cleanser.

Avoid tight clothing, wash your workout gear regularly and try to keep your body cool by staying in the shade and avoiding the midday sun. If your skin is bothering you, speak to a doctor or pharmacist for advice as you could be mistaking your spots for a heat rash.

Heat rash

A heat rash, also referred to as prickly heat, is an uncomfortable but harmless rash that is caused by excessive sweating.

When your sweat glands become blocked, the trapped sweat can cause a heat rash to appear within a few days. The symptoms of a heat rash are:

  • Small, raised spots
  • An itchy, prickly feeling
  • Mild swelling

The rash usually looks red, but this may be less obvious if you’ve got darker skin. To calm your heat rash down, apply a cold pack or damp cloth to the affected area of skin for up to 20 minutes.

Instead of itching, try to tap or pat the rash instead so you don’t irritate it further. There are plenty of treatments available for a heat rash such as calamine cream or a prickly heat powder.

If your heat rash is particularly bothersome, your doctor may recommend a hydrocortisone cream (except for pregnant women and children under 10).

What would happen if we didn’t sweat?

Whilst the prospect of never having to deal with sweat would be pretty convenient, it would potentially cause serious harm.

If you didn’t sweat, your body wouldn’t be able to cool itself down efficiently and you would overheat. Overheating is certainly no laughing matter and can even lead to fatal outcomes.


Anhidrosis, also known as hyperhidrosis, is a condition characterised by the inability to perspire (sweat) properly. It can be caused by advanced age or other conditions that affect your nerves such as diabetes, alcoholism or Parkinson’s disease.

Skin damage from severe burns can also cause anhidrosis, as can radiation, heat rash and psoriasis. Dehydration or prolonged exposure to heat can cause anhidrosis to occur as well.

People with anhidrosis typically experience the following symptoms:

  • Minimal sweating, even when other people are sweating heavily
  • Muscle cramps or weakness
  • Dizziness
  • A flushed appearance
  • Feeling overly hot

Sometimes, anhidrosis will only affect one part of the body and therefore can often go unnoticed. However, anhidrosis can often cause the body to overheat, potentially leading to heat exhaustion or heatstroke.

Heat exhaustion and heatstroke

It is important to know the symptoms of heat exhaustion and heatstroke, so you’re able to take action accordingly if you or a loved one appears to be suffering.

Heat exhaustion typically causes a headache, dizziness and confusion, loss of appetite, nausea, pale or clammy skin, cramps in the arms, legs or stomach, fast breathing or pulse, extreme thirst and a high temperature of 38C or above.

If you think someone might have heat exhaustion, you need to move them to a cool place immediately and have them lie down with their feet raised slightly.

Have them drink plenty of water and cool their skin with cold packs around the neck and armpits, cool water or a fan.

They should start to feel better within 30 minutes, but if they don’t, they could be experiencing heatstroke. Heatstroke is a medical emergency and you need to call an ambulance if you notice any of the following signs:

  • Not sweating even while feeling too hot
  • A high temperature of 40C or more
  • Fast breathing or shortness of breath
  • Feeling confused
  • A fit (seizure)
  • Loss of consciousness
  • Unresponsive

Put the person in the recovery position if they’re unconscious and wait for an ambulance to arrive.

Heatstroke can be avoided by avoiding the sun between 11am and 3pm, drinking plenty of water, taking cool baths or showers, wearing light-coloured, loose clothing, and avoiding excess alcohol and extreme exercise.

Alexandra Moses - Medical Content Writer
James O'Loan - CEO & Superintendent Pharmacist
James O'Loan , CEO & Superintendent Pharmacist on 18 September 2023
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