Gastrointestinal Complaints and Correlations with Self-Reported Macronutrient Intake in Independent Groups of (Ultra)Marathon Runners Competing at Different Distances This study examined the differences in gastrointestinal and stress-related complaints between groups of runners competing in different running routes, using web-based questionnaires. A total of 89.3% of the runners were reported heavy complaints during the race, compared with 70.6% after the race. Significant differences between the groups have been described for marathon runners and ultramarathon runners. During the competition, the runners reported about urinary rang (47.7%), muscle cramps (43.6%) and belching (43.6%).The prevalence of bloating, flatulence, side pain and dizziness was different in different running tracks. There were small to medium-sized negative correlations between food intake and fluid intake and gastrointestinal complaints. After the competition (12 h), 70.6% of the participants assessed complaints, with muscle cramps (47.6%), wind disruptions (19.0%) and flatulence (12.7%) most common.The frequency of belching, nausea, stomach cramps and muscle cramps differed between the distances. There were small to high positive correlations between complaints during and after the competition. In summary, runners of all distances reported a high prevalence of gastrointestinal complaints and other stress complaints. There were some small differences in terms of the type of message and the severity of the complaints between the distances.
The results showed small to strong correlations between complaints during and after the competition and with nutrient uptake, without a clear similar pattern for all distances. The whole work can be found under https://www.mdpi.com/2075-4663/7/6/140