Friday, May 21, 2010

Oh that feeling...

From a running times article
Avoiding Gastric Distress During Runs and Races
Simple dietary strategies for avoiding distaster
By Jackie Dikos, R.D.
As featured in the May 2010 issue of Running Times Magazine
Most of us have faced stomach cramping or the urge to find the nearest secluded tree while running. In training, this can be uncomfortable, embarrassing and a hindrance to an effective workout. (And it can irk your training partners if it happens often enough.) When racing, a pit stop can be downright disastrous, as Deena Kastor, who lost the lead pack at last fall's Chicago Marathon when she stopped at a portajohn, can tell you. Why are so many runners so prone to these intestinal issues, and what can we do to avoid them?

After you eat, the meal must be broken down in your stomach and small intestine for it to be absorbed and utilized. The meal's size, solidity, fiber content, and mix of macronutrients (carbohydrates, protein, and fat) all influence how quickly the food is absorbed.

Take, for instance, a simple carbohydrate-based snack of a banana and crackers. Such a snack would leave your stomach quickly. Mix the banana with a serving of nonfat yogurt, and the time to digest lengthens because of the protein in the yogurt. Spreading peanut butter on the crackers might make the snack more satisfying but also adds fat, which lingers in the stomach the longest.

To help process, absorb, and clear the banana and crackers from your digestive tract, blood flow is diverted from areas of the body with less need and increases in the direction of the stomach and intestines. There's also a secretion of hormones that support intestinal movement and the release of digestive enzymes. It's a whole progression of mixing and moving of digestive juices and food into smaller particles from the stomach through your intestine.

The snack is finally digested as nutrients that are absorbed through the intestinal walls or waste products, like undigested fiber, that are pushed along into the colon and eventually expelled with a bowel movement.

FEELING GRAVITY'S PULL


Why does running conflict with the digestive process? Imagine trying to run on a sidewalk with a buddy nudging you along the way. It might get frustrating after a while because the nudging would make it a lot harder to stay on the sidewalk. Your gut feels the same when you're running. When your body has food to digest, the running motion nudges your digestive tract, making it harder to control the course your food wants to take.

In addition, while you're running, working muscles take priority; blood is diverted from your digestive tract, and it functions less efficiently. There's also an increase in those gastric hormones that help things move along. In general, the harder you run, the more these effects are amplified. Anything from a little gas and cramping on up to nausea and diarrhea can result.

EAT AND RUN

To minimize on-the-run stomach pain and pit stops, the first step is to be well-hydrated. Dehydration leads to even less blood flow to the digestive tract, slowing your body's ability to empty and absorb what you put in your stomach. As a result, constipation can develop, making it more difficult to empty your bowels before heading out for a run.

Dehydration also challenges your body to absorb the fluids, gels, and other forms of fuel you might take in during a run. This can lead to further dehydration and developing GI distress, especially during long, intense events such as a marathon. Go into all runs well-hydrated and stick to a hydration regimen during long runs to facilitate ideal absorption under each given circumstance.

Proper hydration supports the absorption of gels, but be wary of taking sports drink with your gel. Doing so can create a too-concentrated intestinal environment that makes digestion difficult. Take at least 6-8 ounces of water with every gel packet. If you're also drinking a sports beverage, do so no less than 20-30 minutes from taking the gel.


Tolerance as to the timing of meals is very individual. It's best to give your stomach and intestines time to clear most, if not all of a meal before running. Although some people can seem to finish their breakfast on the way out the door for a 10-miler, most runners do best by leaving three to four hours between a meal and a run. Sensible snacks can be eaten one to two hours before a run. The last meal before a run should be relatively easy to digest and shouldn't leave you feeling overly full or bloated.

Keeping in mind the way diet consistency influences how quickly food is absorbed, aim for a less complex pre-run meal that:

* Is low in fiber

* Is low in fat

* Contains a moderate to low amount of easy-to-digest protein

* Isn't overly concentrated with sugar

* Is reasonable in volume

Fiber can be effective in promoting regular bowel patterns. If, however, you're not used to regularly eating high-fiber foods, then that's all the more reason to avoid them soon before a run. Even if you regularly eat high-fiber foods, consider limiting fiber in your pre-run meal and possibly the day before a race.

If you know you're sensitive to lactose, limit or avoid dairy products soon before a run. As with fiber, they're part of a well-balanced diet, so be sure to include dairy products at other times of the day when they're less likely to interfere with your running.

A little caffeine or a warm beverage might do the trick in assisting with a pre-run bowel movement. But if you botch the timing, they might very well accelerate any on-the-run pit stops. Consume such bowel stimulators with ample time to use the restroom before your run or avoid them completely.

POTENTIAL TRIGGERS FOR GI DISTRESS
     
  • Degree of hydration
  • Timing and consistency of diet
  • Increase in running intensity relative to current level of fitness
  • Preexisting conditions such as lactose intolerance or irritable bowel syndrome
  • Stress, excitement, nervousness      

WAYS TO LESSEN RUNS ON THE RUN
 

  • Test sports drinks, gels, and other fuel sources during training runs before using them in races
  • Stick with familiar foods on race day
  • Write down what you eat to identify potential food triggers
  • Avoid sorbitol, a sugar alcohol found in sugar-free foods and candies that can have a laxative effect
  • Consider training at a different time of day
  • Experiment with pre-run liquid meals   

JACKIE DIKOS is a registered dietitian and 2:45 marathoner. Read her twice-monthly sport nutrition column at runningtimes.com/fuel.

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