Digestive problems in athletes

More than one long-distance athlete is likely to have suffered digestive discomfort or at least heard of it from other athletes.

• In the sports event, blood flow increases in the legs and decreases in the digestive system, slowing down intestinal absorption and causing gastrointestinal discomfort.
• In tests that involve impact on the abdominal muscles (runners or triathletes), more digestive problems are suffered than others without such impact (cyclists or swimmers).
• Measures can be taken to prevent digestive discomfort in sports events, such as avoiding certain foods, adjusting the amounts of carbohydrates and hydrating well.

These are the most common digestive problems in long-distance athletes:

• Reflux: feeling that food is returning from the stomach to the mouth • nausea or retching: the urge to vomit without actually doing it.
• Gas, both belching and flatulence, especially if you have eaten foods rich in fiber.
• pain or heartburn sensation, most likely due to lack of blood supply.
• Vomiting: expulsion of stomach contents through the mouth.
• : intestinal disorder characterized by increased frequency, fluidity, and often volume of bowel movements.
• gastrointestinal bleeding: loss of blood in the digestive system.

This symptomatology can make it really bad, or even that we will not be able to finish the competition. In addition to being quite common, between 30-90% of athletes suffer from them, they can be mild annoyances that hinder performance, or serious, to the point that they make us abandon, and even very serious and become serious problems of health.

Why do they occur?

Knowing the causes can help us prevent digestive problems in athletes and prevent them from happening again. A single cause cannot be indicated, but rather is produced by a series of factors that can alter the normal state:

• Decreased blood flow to the digestive system: When performing intense physical exercise, blood flow is focused on the musculoskeletal system, going from 15-20% at rest to 70-85% during intense exercise. On the contrary, the digestive system goes from receiving 20-25% at rest to 3-5% with intense exercise. This causes both gastric emptying and intestinal absorption to be much slower and causes gastrointestinal discomfort.
• Dehydration: an inadequate one favors the appearance of digestive discomfort, since it decreases the volume of the blood so that even less flow reaches the digestive system.
• Hyperhydration: excess fluid can cause nausea due to hyponatraemia (occurs when the concentration of sodium in the blood is below 135mEq / L, since sodium is necessary to regulate blood plasma).
• Carbohydrate consumption: a low consumption of carbohydrates during the sports event can cause hypoglycemia (low blood sugar) and, as a consequence, the appearance of nausea. On the contrary, an excess of carbohydrates in high concentrations, for example, mixing gel + isotonic drink, can cause nausea, vomiting, abdominal pain or diarrhea. This is due both to the amount of water that passes into the intestinal lumen to counteract the high concentrations of sugar and to the remains of sugars that may remain in the intestine.
• Consumption of other foods: those that are high in fiber (very fibrous fruits and vegetables), fats (stews, fried foods, sausages, fatty meats or fish ...), protein (large amounts of protein foods), and those that are rich in fructose (various pieces of fruit or fruit juices) are foods that can also cause digestive discomfort. Also a consumption of hypertonic drinks (with a very high concentration of carbohydrates and / or salts) is associated with digestive problems.
• Mechanical factor: In those events in which athletes suffer an impact on the abdominal muscles, such as runners or triathletes, they suffer greater digestive problems than other disciplines that do not receive such an impact, such as cyclists or swimmers.
• Psychological factor: The stress generated by the sports event can cause gastrointestinal discomfort, especially in people with worse emotional management in stressful situations.
• Duration and intensity of exercise: the longer the duration and intensity of the test, the blood flow decreases to the digestive system, thus increasing the symptoms.
• Consumption of Non-Steroidal anti-inflammatory Drugs (NSAIDs), that is, drugs such as “ibuprofen”: this type of medicine increases the permeability of the intestine and favors intestinal “micro-lesions” that appear during intense exercise.
• Individual factor: Those people who have suffered digestive problems in other sports events or with problems in their day to day (heartburn, reflux, hiatal hernia, gastritis ...), are more likely to appear such problems.

What steps can we take to prevent digestive problems?

• Carbohydrates: whether in the form of gel, bar, gummy ... they should be taken with small sips of water, never with another sugary drink since there would be an overload of sugar in the stomach that would delay gastric emptying.
• Other foods: The day before and on the day of the competition, avoid beverages rich in fructose, such as fruit juices, foods very rich in fiber (legumes, highly fibrous vegetables, whole grains), which, on the contrary, are fully recommended in training stages.
• Hydration: Good hydration should be maintained during the test, taking small sips, and although the amounts are very personal, it is advisable to start drinking early (after one hour) in order to replace all the water lost due to sweating (approx. 250 ml each 15 min, or 500 ml every 30 min). It is also advisable to be well hydrated before starting the test (500 ml of liquid two hours before exercise to promote adequate hydration and allow time for the excretion of excess ingested water).
• NSAIDs: They should be avoided both before and during the test, due to increased intestinal permeability, although in general any medication (except chronic ones).
• Try a new food or supplement first: It should never be done on the same day as the sports event, because only if we do it beforehand will we know if it is appropriate and if it suits us.
• Take the pre-race intake a minimum of two hours before.
• Easily digestible foods: During the race it is advisable to take easily digestible foods such as bananas, dates, dried figs, isotonic drink, gels, bars ...