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By: Daniel X. O'Neil

How To Fix Your Endurance Stomach Problems

When your pushing through a hard workout or race, the last thing you want to worry about is having an upset stomach. It’s an unfortunate fact that many endurance athletes (including high-level pros) still face depilating stomach issues that have them racing from porta potty to porta potty instead of to the finish of the race.  The good news is by following the advice below combined with some trial and error, you can get rid of these stomach and focus on Racing!


Problem 1: Excessive nutrients (too many calories at once)

After finishing (or surviving) the swim portion of a triathlon many athletes think they need to start taking calories as soon as they get on the bike so they can fuel themselves for the rest of the race. While this is a good strategy to some degree, the problem is taking in too many calories at once which can excessively fill the digest tract causing stomach stress.

Solution: Instead of taking down 100 calorie gel or a huge swig of sports drink, break consume up into smaller bites. For example, take in just a small bite (1/4 of a gel or 25 calories) followed by some water. Wait a few seconds then continue. If you’re taking your fuel through a liquid, take small sips every couple of minutes instead of large gulps.

Problem 2: Excessive fluids (too much water)

Drinking huge amounts of water can also contribute to stomach problems and provide a very unpleasant stomach sloshing.

Solution: Don’t over-hydrate before and during your training session or event. Simply drink to thrust before and during the event with water. For most athletes this is 24-48oz (2 bike water bottles) of water per hour on the bike and about half that on the run.

Problem 3: Dehydration

Just as you can take in too much water, you can also take in too little water. I found this happens most often when individuals travel to race in a much hotter environment.

Solution: Pay attention to thirst, and be sure to always carry a water bottle with you leading up to a hot race or training session, and plan how you will hydrate during the event (I.E. Carry an extra bottle for hot races).

Problem 4: Eating to close to workout

As in explained in How to Take Charge of Your Pre-Workout Meal, a common problem athletes encounter is eating to close to a training session or race. If you’ve done this (most every athlete has), typically you know right away as you start burping up what you just ate.

Solution: Wait 2-3 hours after eating a meal before jumping into a training session or race. If this is not possible eat a really light carbohydrate such as a gel or small banana within an hour of your training session or race.

Problem 5: Mystery reason

Even following all the advice above,  triathletes still have stomach problems and simply don’t why. Don’t worry your not alone, and there is a solution.

Solution: Follow Coach Brad’s happy tummy 3 step protocol recommendations:

1st- Try different brands of products, maybe GU just doesn’t work for you but Hammer gels do for example

2nd- Consider trying different types of fuel, (I.E. if gels don’t work, try liquids, if liquids don’t work try solids, etc.).

3rd- Carry peppermint tums (peppermint flavor doesn’t have any artificial colors) with you during long duration triathlons as a safety net for any unexpected stomach issues.

In you’ve tried everything above and are still having problems, contact me and I will certainly try and help you out. I would hate to see anyone have a raced ruined because of an upset stomach.

About Brad Haag

Brad is a certified USAT triathlon coach, a certified USAC cycling coach, and a certified NCSF personal trainer. Brad specializes in coaching endurance and warrior class athletes to peak performance. He can be found at HaagsAthletics.com.


  1. Constipation and dehydration is not good at all.

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