Gastrointestinal (GIT) symptoms in athletes: a review of risk factors associated with the development of GIT symptoms during exercise.

Gastrointestinal tract (GIT) symptoms commonly affect endurance athletes. Although a number of risk factors for the development of GIT symptoms during exercise have been proposed, scientific evidence in support of these factors is limited. In this review article, the risk factors associated with the development of GIT symptoms during exercise will be critically reviewed. An extensive literature review was conducted using an evidence-based approach. Using selective keywords (gastrointestinal tract symptoms, exercise, risk factors, athletes, triathletes) a search was undertaken using the PubMed database to identify all research publications that relate to the development of GIT symptoms during exercise. There is strong evidence from a limited number of studies to support significant dehydration (body weight loss >4% during or after exercise) as a risk factor for GIT symptoms during exercise. However, more research studies are still needed to support this finding. There is some, but limited scientific evidence, to support the following as risk factors for GIT symptoms during exercise: female gender, younger age, high intensity exercise, vertical impact sport and medication use. Poor conditioning, dietary factors and previous abdominal surgery are risk factors for GIT symptoms that are not well supported and evidence is considered weak in these areas. Therefore, further research studies of greater power, such as case control and prospective cohort studies are needed in order to evaluate risk factors adequately. Subject selection needs to be random and subjects should not be self-selected. Data needs to be collected in an objective manner not relying on subject recall. Measurement parameters also need to be standardised. In conclusion, there is very little evidence-based research to support the majority of the currently suggested risk factors for GIT symptoms in endurance athletes and further research is essential.