Exercise induced GI distress in endurance athletes

Gastrointestinal or G.I. problems are quite common and endurance athletes often impairing their performance. This common problem is that the blood flow to the G.I. tract is reduced during the exercise and contributes to the unpleasant symptoms. Decreased blood flow to the intestines or gut ischemia can lead to nausea, vomiting, abdominal pain and diarrhea.
The marathon legend, Bill Rodgers back in the 1970’s once said that many marathons are won in the Porta-potties rather than the dinner table. Many of us have been there at one time or another, and it is not a pleasant place to be.

This reduced blood flow to the stomach and intestines is due to the redistribution of blood flow that is diverted to muscles, heart, lungs, and brain. Other reasons for upset and symptoms are the effects of running itself, bouncing up-and-down, jostling your intestines so that resembles disorganized bowl of spaghetti. This can sometimes lead to “runners gut”, allowing some of the tender intestinal tissues to bleed, producing a black stool. (That in itself should resolve within two days or so, if not please see your physician as soon as possible.)

Since your legs, heart, and lungs are doing all the work, the body is forced to redistribute the blood and oxygen supply to those extremities and organs. The lack of adequate blood flow alone can cause some damage to the delicate intestinal tissues. If you are even mildly dehydrated to begin with, you may set yourself up for disaster as you are not able to eat and keep food down – you need adequate blood flow to the stomach to digest the food.
Quite the conundrum.

The key to reducing G.I. distress – hydrate early and train your gut

Your stomach is very adaptable and trainable, and it’s important to keep it alive and well before and during the course of your endurance run. It is also important to pre-hydrate before your run and consume small amounts of nutritional replacements along the way, thus keeping your gut “awake” for absorbing the nutrients your body needs to complete your run. Unless you start early and keep your digestive tract awake, your stomach will reject both fluids and solids – they are either go up or down, and most likely you will not feel like finishing the race.

Of course these are not all of the reasons for having stomach distress along the trail, but I have found them to be the most common in many of the runners that I have treated, that skip hydrating and eating until it’s nearly too late to rejoin the race.

Short and sweet this time… If you would like any further in depth explanations, please do not hesitate to contact me or Jenelle.

~ Spike