Dietary and non-dietary correlates of gastrointestinal distress during the cycle and run of a triathlon

Eur J Sport Sci. 2016;16(4):448-54. doi: 10.1080/17461391.2015.1046191. Epub 2015 Jul 29.


The purpose of this investigation was to assess whether pre-race dietary and non-dietary factors were associated with gastrointestinal (GI) distress during the cycle and run of a 70.3-mile triathlon. Fifty three participants recorded dietary details the day before and morning of the triathlon and retrospectively reported GI symptoms from the cycle and run. Occurrence and severity of nausea, regurgitation and fullness were combined into an upper GI (UGI) category, while lower abdominal cramps, flatulence and urge to defecate were combined into a lower GI (LGI) category. Spearman's rho coefficients were used to examine whether UGI and LGI were associated with: (1) pre-race diet (kilocalories, carbohydrate, fibre, fat, protein, caffeine); and (2) non-dietary factors (age, body mass index, experience, weight change, GI distress history, finishing time). Of non-dietary factors, only a history of GI distress showed significant associations with GI symptoms during the triathlon (ρ = .32-.36; P < .05). Morning kilocalorie (ρ = .28, P = .04) and carbohydrate (ρ = .36, P < .01) intakes were modestly, positively associated with UGI during the cycle, while morning caffeine intake (ρ = .30, P = .03) showed a modest positive association with LGI during the run. The associations between diet and GI distress variables remained significant after adjusting for non-dietary factors. Competitors of 70.3-mile triathlons should carefully weigh the benefits of higher race-morning energy, carbohydrate and caffeine intakes against their potential to increase GI distress.

Keywords: Endurance; exercise; nutrition.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abdominal Pain / physiopathology*
  • Adult
  • Caffeine / administration & dosage
  • Diet*
  • Dietary Carbohydrates / administration & dosage
  • Energy Intake
  • Female
  • Flatulence / physiopathology
  • Gastrointestinal Tract / physiopathology*
  • Humans
  • Laryngopharyngeal Reflux / physiopathology
  • Male
  • Nausea / physiopathology*
  • Running / physiology*
  • Sports Nutritional Physiological Phenomena*


  • Dietary Carbohydrates
  • Caffeine