Gastrointestinal Discomfort In Moderate Running: Effect Of Body Mass Adjusted Carbohydrate-electrolyte Drink Volume

Abstract

Especially in endurance exercise such as marathon and triathlons, is not uncommon to see an increased incidence of GI symptoms associated with food and beverage intake before and during exercise. PURPOSE: To investigate the effect of two volume of carbohydrate-electrolyte (CHO) drink according to the body mass (BM) during one-our running performance on the gastrointestinal (GI) tract and to verify if BM could be an optional parameter of fluid replacement. METHODS: Thirty-two individuals;16 men (23.3 ± 1.3 years) and 16 women(21.7 ± 1.7 years) performed three runs on a treadmill at 75% VO2max during 60 min. In this time, the subjects drank a 6% CHO solution in set volumes of 2 or 3 mL. kg-1 BM (LV and HV; respectively) every 15 minutes. GI complaints were evaluated by a short questionnaire requested to verbally answer at every 15 minutes. Glycemia, ratings of perceived exertion (RPE), and thirst sensation were also evaluated at this same period of time. RESULTS: The most occurrences of GI complaints were observed in men than women. The most frequency of GI complaints was related at 45 and 60 min. The most frequent symptom in HV was urging to urinate indicated by 75% men at 60 min and 81.2% women at 45 min. In LV this perceptual were of 62.5% and 50% for men and women respectively. There were no register of severe symptoms for women in all the trials and for men during LV trial. Only one man in HV indicated a score 6 for severe symptoms (stomach problems, bloated feeling and stomach cramps) from 30 minutes. At 15 min both in HV and in LV was observed the lower glycemic mean for men (5.19 ± 0.57 mmol.L-1; 5.16 ± 0.72 mmol.L-1 respectively) and women (5.06 ± 0.61 mmol.L-1; 4.83 ± 0.46 mmol.L-1). At 60-min LV women presented a light lower thirst sensation than men (p = 0.02). In all the trials RPE was higher (p < 0.001) at 60 min than at 15 min and at 45 min than at 30 min. CONCLUSION: The data demonstrate that ingestion of 2 or 3 mL.kg-1 BM of a 6% CHO drink at every 15-min during 60-min run is effective in maintenance of blood glucose and did not caused severe GI symptoms that would compromise performance and health, presuming that, the use of body mass as an optional parameter of fluid replacement is rising such as practical and nonaggressive method for studies involving the GI tract.