Gastrointestinal disturbances are not uncommon in runners, particularly marathon runners. According to Rice University, studies on marathon runners and triathletes have shown that 40 to 50 percent of them experienced some kind of intestinal complaint during or after competing. Taking preventative measures to adjust your eating and drinking habits can help, but if you consistently experience intestinal discomfort while running, consult a doctor to rule out an underlying gastrointestinal disorder.
Running & Digestive System
When you are running a marathon, your blood gets shunted away from your intestines, out to your extremities. This provides your muscles with the extra oxygen they need to function, but it impairs the digestive process. In addition, the impact caused by your feet hitting the ground jars and jostles the intestines. If you eat too much much before a race, have problems digesting certain foods, or have an underlying intestinal disorder, running can lead to diarrhea, cramps, nausea and gas.
Other Causes
While eating too much or eating foods that cause digestive problems are common causes of intestinal discomfort, dehydration and lack of electrolytes can also cause cramping and discomfort. The smooth muscles of your intestines need to be properly hydrated to move, and electrolytes, particularly sodium and potassium, are also required for smooth muscle contraction. If you are consuming gel packs for long-term energy, lack of water to dilute the high sugar content can lead to discomfort and nausea. Overexertion can lead to intestinal discomfort because your body cannot get rid of waste products fast enough, which can lead to nausea, cramping and vomiting.
Prevention
To avoid intestinal discomfort from overeating, eat a smaller meal of 80 percent carbohydrates and 20 percent protein two to four hours before your race. Avoid eating fatty foods or foods with high fiber content; both are hard to digest. Drink water enhanced with electrolytes before and after a race. Drink small sips of water during the race, particularly if you are sweating a lot and running in hot, humid conditions.
Taking problem foods out of your pre-race diet may help. Common culprits are beans, dairy products, whole wheat, caffeine and alcohol. Pace yourself during the race and consider performing more training to build up your endurance. Drink ample water if you are taking gel packs. If that doesn't help, try a different brand of gel pack. Professional running coach Joe English recommends eating a solid meal such as a sandwich with meat 30 to 45 minutes after a race to help calm the stomach and replenish lost nutrients.
Considerations
If you are not having any success by taking preventative measures, consult a doctor. You may have an underlying gastrointestinal problem. Gastritis, irritable bowel syndrome and ulcers are examples of problems that can cause intestinal discomfort, which marathon running may exacerbate. If your discomfort is severe while racing, stop and seek medical attention.
