-- Marathon Running Information, Coaching and Advice from Coach Joe English

Training — How do I deal with Runner’s Diarrhea? (part II)

[This is the continuation of a post. To read part i, click here.]

So how do you avoid runner’s Diarrhea?
Avoiding Runner’s Diarrhea starts by understanding what’s causing the diarrhea in your particular case and then dealing with it. The first place to start is to back off your training intensity and mileage to see if that helps. If it does, then slowly increase the mileage and intensity and hopefully it won’t come back.

Dealing with stomach issues is no fun for #runners

Dealing with stomach issues is no fun for #runners

In many cases, however, the problem will be strictly nutritional, so here you’ll have some work to do. There are many items in the diet that can cause diarrhea in athletes, such as Sorbitol (used in sugar-free gum), Aspartame, Caffeine, and insoluble fiber. In addition, you could be intolerant of one or more of the sugars used in any of the foods that you’re using during your training. Also, the concentrations of sugars in your stomach may be too high, because you may not be drinking enough water to dilute those sugars and keep them from upsetting your stomach. Finally, it may be a matter of when and how much of what you’ve eaten causing the problem.

Here are some things to try to root out the causes of Runner’s Diarrhea:
– Start a journal capturing everything that you’ve eaten and when, along with the start and end times of your workouts, and when the diarrhea started. Try replacing any foods that you’ve eaten prior to a bought of diarrhea or adjusting the amount of time before your workouts to see if this makes a difference.

– Try different brands of gels/bars/energy replacement drinks and note which ingredients are contained in the brands that do and don’t work for you. Pay particular attention to the sugar contents: sucrose, fructose, dextrose, maltodextrin, and glucose are common sugars you’ll find in exercise related foods.

– If you are mixing foods, or foods and fluids together, isolate these and use them separately to see if this helps. A common issue that I see are athletes mixing a sport drink like Gatorade with an energy gel like PowerGel. Stick with one product at a time until you find out which one (or which interaction) may be causing a problem.

– Try natural rather than packaged or engineered foods – for example switching to bananas and PB&J sandwiches rather than energy gels to see if that helps.

Drink more fluid along with energy gels to ensure that you’re properly diluting the sugar in your stomach.

– Cut out suspect ingredients in any food that you’re eating, including Sorbitol, Aspartame and caffeine.

– Reduce the intensity and duration of your workouts and slowly rebuild these, noting how this impacts your diarrhea.

– Ensure that you’re not adding anything new that you haven’t tried before on race day.

Finally, with all of this in mind, don’t panic. When diarrhea strikes, you need to deal with it. If you’re in the midst of training, make sure to experiment with the factors above to understand what’s causing your problem. You may want to consult a sports dietician for help. See the links below to find one.

If you’re in the midst of a race, take corrective action immediately. Stop eating any particular food that might be causing a problem and drink more fluids to prevent dehydration from worsening. Don’t lose your head.

Runner’s Diarrhea is not much fun, but you can deal with it. Just stick to the basics: understand what you’re eating, how much, and when and find the cause of the problem. Through experimentation and trial, you can find the culprit and make the Porta-potties a thing of your past.

Related articles & links:
Ten things you need to know about hydration

Find a sports dietician

Coach Joe English, Portland Oregon, USA
Running Advice and News


5 responses so far, want to say something?

  1. 1. halfawake September 7th, 2007 at 7:25 am

    Do you ever seem to experience “runner’s diarrhea” *before* races? I always have some gastro-intestinal problems before races. I used to think it was because I was nervous, but now it happens even when there is “no pressure” for the race… Usually I eat a bagel and water the morning of a race…

  2. 2. coachjoeenglish September 7th, 2007 at 8:41 am

    Yes, this is another important topic.

    In my training groups I often talk about the “pre-race poop” (or any others number of dirty words at the end).

    The most common cause of either having diarrhea, or not being able to go at all, is related to schedule changes before the race. In a lot of cases, people go to bed earlier, sleep less (they toss and turn all night), and then get up earlier than normal. All of these things throw off the routine and can lead to either type of problem.

    With regard to eating before a race, make sure to eat whatever you eat before your long training runs. And make sure to eat with enough time before the race to let it digest. Again, a lot of people’s schedules get disrupted by getting up super early before a race due to an early start time and breakfast gets jammed in too close to start time. According to nutritionists, it is best to eat as much as two hours before racing – so that means getting up earlier than you might like on race day.

    Also, stress can be a trigger for irritable bowel symptom, so if you have IBS, keep that in mind.

    Finally, don’t throw extras into your breakfast on race morning. I often see people munching PowerBars and gel packs before races. They will usually tell me “I need a little extra-something today” – but since this out of their routine it will often cause problems.

    Happy running (punn totally intended).

    Coach Joe

  3. 3. coachdeanhebert September 14th, 2007 at 5:15 pm

    This is a great topic. It’s just a fact of life if you are a runner that sooner or later it will happen. Very thorough information – good job. Here’s even more on the topic for those interested:

    Upward and onward!
    Coach Dean

  4. 4. Training — How do I deal with Runner’s Diarrhea? (part I) | Running Advice and News September 29th, 2009 at 3:05 pm

    […] To continue on to part ii, click here. […]

  5. 5. Lynne October 14th, 2010 at 10:57 pm

    I have the same experience as halfawake- but I am a coffee drinker too, and have been so forever. Should I reduce the coffee? I am worried about a headache….

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