High-intensity exercise performed at a competitive level can have acute gastrointestinal consequences. Previous studies have observed that between 30-50% of athletes tend to experience gastrointestinal problems on a regular basis [1]. This prevalence is much higher in aerobic disciplines, where it has been observed that between 30-90% of athletes experience some gastrointestinal symptom, with prevalence increasing as exercise intensity and duration rise [2]. The most frequent symptoms are nausea, regurgitation, pain, diarrhea [3], and even stomach pain [4]. Anecdotally, at the 2012 Olympic Games, gastrointestinal problems were the second most common problem in athletes, where a total of 123 athletes (16%) had vomiting or diarrhea [5].
Why do these gastrointestinal problems appear during exercise?
There is really no single cause that determines the appearance of these gastrointestinal problems, since it is a multifactorial condition. Among all the possible causes we could find [1–3]:
- The performance of the exercise itself, especially at high intensity and duration, which causes physiological stress inducing a greater risk of these problems.
- Situations of high temperature and hyperthermia that aggravate the gastrointestinal stress produced by exercise.
- Exercising at altitude.
- Psychobiological factors such as nerves, stress or anxiety, both chronic and acute before a sporting event.
- And of course, nutritional causes such as: pre-exercise intakes high in fat, protein and fiber, intake of hyperosmolar solutions during exercise, situations of dehydration or hyponatremia, and carbohydrate intake such as FODMAPS before exercise or single sources of carbohydrate during exercise.
What are the consequences of these gastrointestinal problems?
The consequences of these gastrointestinal problems can range from mild consequences such as discomfort, to gastrointestinal alterations that lead to severe clinical symptoms (bleeding, inflammation or erosion of the intestinal mucosa, etc.). [2,6]. In addition, the appearance of this symptomatology triggers a decrease in performance. For example, their presence during training affects recovery and workload, while their appearance during competition may lead athletes to withdraw [6–8]. Finally, these symptoms affect the athlete's concentration, reducing performance, and can also trigger psychobiological consequences such as stress, anxiety or emotional problems [9].
Simple guide to prevention and treatment
As we have previously mentioned, the causes are multifactorial, therefore, their approach must also be multifactorial, trying to reduce all the potential risk factors of these problems. The main guidelines are [1–3]:
- Avoid ingesting nonsteroidal anti-inflammatory drugs (e.g. aspirin) before exercise and in the days leading up to competitive events.
- Maintain an adequate hydration schedule before and during exercise, without forgetting the corresponding sodium intake as we have seen in previous articles.
- Carry out adequate gut training before competitive events. For example: do not try quantities and types of food on the day of the competition, avoid trying new supplements or sports drinks that same day, etc.
- In the case of intra-training or intra-competition intakes, use different types of carbohydrates and not just one type.
- Avoid eating meals that are very high in fat, protein (in excess) and fiber before exercise and the competitive event.
- Avoid potentially annoying foods such as: spicy foods, raw vegetables (garlic, onions, peppers), legumes, fried foods, highly spicy foods (e.g. curry), and even dairy products (according to individual tolerance).
- Carry out adequate management of both chronic and pre-competitive stress and anxiety [9].
- Finally, glutamine supplementation (20-50g 2h before exercise) has been shown to improve certain symptoms of gastrointestinal distress [10,11], and may be a useful strategy to prevent the onset of gastrointestinal problems.
Conclusions
In summary, the appearance of gastrointestinal symptoms is common in athletes. Therefore, due to its multifactorial causes, addressing nutrition and the other contributing factors can benefit on the health and performance of athletes.
AUTHOR
Lucas Jurado Fasoli – Doctor of Biomedicine (UGR). Dietitian-Nutritionist. Postdoctoral researcher at the Joint University Institute of Sport and Health and Department of Physiology, University of Granada.
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References
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