How to avoid stomach problems on the run

Unpleasant issues at the business end can hamper your training and ruin your races. Use this guide to identify the causes and make the diet tweaks to help.


by Phillip Latter
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It may not be something you’re comfortable sharing, but if you’ve experienced on the run what we’ll call, for the sake of decorum, a ‘Paula moment’, rest assured you are not alone. A study in Current Opinion in Clinical Nutrition and Metabolic Care found that 30-50 per cent of runners experience lower gastrointestinal (GI) distress during long or intense runs, including diarrhoea, abdominal cramping and an immediate urge to defecate.

But this is not something you simply have to live with. ‘People shouldn’t be hopeless and helpless,’ says Nancy Clark, sports nutritionist and author of Sports Nutrition Guidebook (Human Kinetics). Fortunately, a growing body of research is shedding light on this once-taboo subject, and there are solutions to the problem.

Running is an inherently violent, jarring sport on the body and no organs feel this more than your stomach and colon. Mechanical distress causes food and waste to move through the GI tract more rapidly when you’re running. Blood is also diverted from the intestines to working muscles, lowering their functionality. This predisposes runners to lower-GI problems, but experts say you can limit your suffering by managing other variables, including diet, dehydration, lactose, gluten intolerance, and even nerves. There’s no cure-all, but here are a few ways you may be able to stop the trots in their tracks.

Modify and monitor your diet

Most runners find the cause of their lower-GI distress is diet-related. The simplest modifications – such as avoiding foods that are high in fibre or fat, or contain irritants, in the days before a race or run – can keep problems at bay, says Clark. In their place, eat naturally constipating foods such as white pasta, white rice and bananas.

A good way to detect your personal food triggers is by keeping a diary of your food and your bowel movements. Remember that for the average person, it takes between 24 and 72 hours for food to travel from gut to U-bend, with runners tending to be on the faster side.

Whatever you do, don’t stop eating. ‘I’ve had runners so afraid of a pit stop that they don’t eat or drink anything during a marathon,’ says Clark. ‘Some of them get to 15 or 20 miles on just air, but they generally end up in the medical tent.’

If you continue to experience frequent lower-GI distress or see blood in your stool, you should consult a doctor, who can detect any underlying problem, says ultra runner and sports medicine specialist Dr Cathy Fieseler. Lactose and gluten intolerance (including coeliac disease), as well as irritable bowel syndrome (IBS), Crohn’s disease and ischemic colitis all make you more susceptible to lower-GI distress.

Establish a routine

Your bowels are creatures of habit, so when routines change the consequences can be dire. One thing all runners should avoid at all costs is introducing new foods and/or drinks on race day. So if you’re planning to take fluids or gels during a race, practice with them during your training to make sure you can tolerate them.

US elite marathoner Deena Kastor suggests getting up earlier on the big day so there is time to eat a good meal and use the toilet. ‘It’s difficult to get up at 4am, but it will ensure a more comfortable race,’ she says. Also, many runners find that a short run several hours before a race provides the stimulus to get their systems moving.

Stay hydrated

Sweating away over four per cent of your body weight greatly increases your risk of diarrhoea while running, so the fluids you take on may help prevent it. Not coincidentally, runner’s trots are most common at the end of a long run. Diarrhoea has extremely high water content, making it a cause of dehydration. Ensure you take in fluids before, during and after exercising.

Drug problem

Runners with bouts of lower-GI distress often turn to medication and/or invasive procedures to remain accident-free on the run. Of these, the safest course is a dose of anti-diarrhoea medication, such as Imodium. Fieseler says using Imodium is probably safe if you don’t get bloody diarrhea, you have no trigger foods and you suffer only on long or intense runs.

Blocking up is one thing, but flushing out is more risky. At the other end of the spectrum are runners who purge their intestines with chemical laxatives, enemas, bowel preps and colonic irrigations. These can alter your electrolyte levels and have major side effects, including nausea and stomach cramping. ‘The more aggressive the bowel programme, the greater the possibility you’ll have electrolyte abnormalities,’ says Fieseler. ‘You’re dancing with the devil.’

(Sh)it happens

Embarrassing and inconvenient as untimely GI issues undoubtedly are, you need to accept that they are part and parcel of a sport that shakes things up – and often loose – down there. Visits to the portable toilet may add seconds – or minutes – to your finish time, but there will always be other races. Urgent calls of nature may occasionally place you in some compromising positions, but try to see this as a badge of honour. It’s all part of being a runner. Just ask Paula…

READ: 6 common GI issues and how to fix them

READ: Science of digestion

READ: 6 easy steps to avoid stomach issues


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gi problems, runner's trots, diarrhoea, ibs
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Got rid of dairy before the race first - helped a little bit, but cutting out wheat has really helped. Stomach fine EVEN after cross country now!


Posted: 10/03/2016 at 09:04

  I stopped eating bread, made a massive difference to my "  bowel  movements "


Posted: 10/03/2016 at 18:34

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