Runner’s Gut

The urgency to find a bathroom (also known as runner’s “trots” or runner’s gut) can ruin a perfectly good training session!  For some it is a grumbling sensation, pain in the stomach, or bloating; but for others, toilets must be publicly accessible at regular intervals. This is not only disruptive in training and competition but can also create anxiety, ultimately compromising performance.

Who is at risk of Runner’s Gut?

  • Runners are more likely than other athletes to experience bowel discomfort during exercise.
  • Those prone to nervous anxiety
  • Elite athletes are more at risk than recreational athletes
  • Younger athletes

What causes Runner’s Gut?

There are several factors outlined below that may be linked to gut discomfort during exercise. It is highly recommended you consult with a sports dietitian to develop a management plan for your GIT (gastrointestinal tract) issues.


Dehydration increases the risk of nausea, vomiting, diarrhoea and other gastrointestinal problems during exercise.  Always start exercise well hydrated; this will reduce therisk of becoming dehydrated during sport.

Highly concentrated carbohydrate drinks

Drinking fluids with a high carbohydrate concentration (greater than 10% – e.g. soft drink, fruit juice and energy drinks) can cause diarrhoea and gut issues during exercise as they draw extra water into the gut. Standard sports drinks (4 – 8% carbohydrate) are usually less likely to cause gut upset.

Reduced blood flow to the gut

A lack of blood flow to the gut (ischaemia) has been shown to be the main cause of nausea, abdominal pain, vomiting and diarrhoea.  During exercise blood is redirected from the gut to the working muscles (e.g. legs) which can create issues with stomach comfort.

Timing of the last meal before exercise

Eating too close to exercise doesn’t allow the stomach enough time to digest the food eaten. Although everyone is different, a good general rule is to avoid eating a main meal within the 2-4 hours before exercise.

The type of food eaten just before exercise

High fibre, fat and protein meals consumed pre-exercise have been shown to cause an increase in GIT symptoms as fibre, fat and protein are slow to empty from the stomach.

Gut-related medical conditions

Coeliac disease is a genetic medical condition that results in a permanent intolerance to gluten and can cause GIT symptoms if undiagnosed or poorly managed. Irritable bowel syndrome, lactose intolerance and fructose malabsorption have been suggested to be associated with the development of GIT symptoms that can be exacerbated during exercise.

How to avoid Runner’s Gut

As there are many factors that can trigger unpleasant GIT symptoms during exercise, consulting with an Accredited Sports Dietitian will help you to determine which possible trigger/s may be the cause of your runner’s gut and plan individualised strategies to help avoid them.