Unintentional Water Intake During Swimming and Post-Race Gastrointestinal Illness in Triathletes: Results from 6 Triathlons and 1294 Athletes.

This study aimed to investigate the relationship between water intake and post-race gastrointestinal illness in triathletes. Following a post-event survey approach, we evaluated the association between water intake and gastrointestinal illness in triathletes. We collected data among participants of six different triathlons in the Netherlands using an online questionnaire about personal characteristics (age, sex, swimming experience, chronic illness, and athletic level), the completed triathlon (length and duration), water intake, and illnesses during the 7 days following the triathlon. The associations between water intake and gastrointestinal illness were analyzed using generalized estimating equations logistic regression. In total, 1294 athletes participated in this study. The average rate of gastrointestinal illnesses per triathlon was 5.1%. In total, 75.3% of the athletes reported water intake during the race. The associations between water intake and gastrointestinal illnesses were significant. Triathletes with one to three sips of water intake reported 3.7 times more gastrointestinal illnesses (OR = 3.672, 95%CI: 1.316-10.242, p = 0.013) compared to those who did not ingest water. Triathletes with four or more sips of water intake reported 5.1 times more gastrointestinal illnesses (OR = 5.070, 95%CI: 1.740-14.767, p = 0.003). In conclusion, water intake was associated with an increased risk of post-race gastrointestinal illness. The results advocate for improved water quality monitoring and preventive measures in triathlon.