If you suffer with IBS, you may be experiencing a change in your symptoms with the hot weather during this summer.

There are a number of reasons why the heat can change our symptoms.

Dehydration affects IBS

Firstly, when it’s very hot, we will typically sweat a lot, which can lead to dehydration. When we don’t have enough water in our digestive system it simply won’t operate as effectively.

This means you could get extra bloating, gas, or stomach pains, due to fermenting foods inside your gut.

The best way to tackle this is to stay hydrated by maintaining your liquid intake throughout the day, aiming for eight glasses of water. As a minimum around two litres.


glass of water with ice, against a black background

You change your diet in hot weather

Another reason why our digestive system could be under more pressure when it’s very hot outside we tend to want to eat cold raw foods.

Now this may be different from the foods that you typically eat, and some people with a sensitive tummy may find that raw foods are more difficult to digest. And again, may lead to bloating and excess gas.

Less movement affects IBS

Also when it’s very hot, we tend to do less exercise and move our body as little as possible, which may change the frequency of your bowel habits.

If you’re prone to constipation you may find your symptoms get a little worse because either you’re dehydrated and the stools are becoming hard, or the fact that you’re moving a lot less may be decreasing the physical triggers for a bowel movement.

slices of watermelon, glass of water with ice and mint on a wooden board

Heat preventing sleep may make IBS worse

When it’s very hot, we tend to struggle to sleep. And when we’re tired we feel our pain more.

So if you’re someone who experiences digestive, or abdominal pains, then you may be more sensitive to these during periods when you’re very tired.

Hot weather can impact on our ability to sleep, which has a knock on impact on our sense of pain within the body.

Some people with IBS are more sensitive to heat

One study showed that people who have IBS feel more sensitive to heat than controls.  If you have IBS you’re more likely to be sensitive to pain.

Don’t confuse IBS diarrhoea with heat exhaustion

If you’re someone who typically experiences very loose stools, or at the moment you have got diarrhoea, then do, make sure that you are well hydrated because diarrhoea can be a sign of heat exhaustion.

Heat strokecan also include symptoms such as aches and pains rashes excess sweating.

If you have any of these symptoms, then do speak to a doctor to get yourself checked out.

How to stay cool with IBS and reduce flare ups

Helpful ways to keep yourself cool include:

  • Maintaining your liquid intake aiming for two litres of water a day.
  • Putting a cool flannel on your head or face,
  • sitting in the shade using fan, or air conditioning, if that’s available to you.

Eat well for the hot weather


  • Stick with foods you know don’t aggravate your symptoms, even that beer, ice lolly or salad looks tempting
  • Some foods are linked to keeping the body cool and hydrating and these include refreshing foods high in water content such as watermelon, cucumber, salads and fruit.

    Hi I'm Anna Mapson, registered Nutritionist (mBANT, CNHC). I help people with IBS, SIBO, reflux and other gut health issues.

    I can help you to:

    • understand your digestion better, so you recognise your triggers
    • eat a well balanced diet, with tasty meals that are simple to prepare
    • develop healthy, sustainable habits for life

    “Anna is amazing! I feel totally transformed"

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