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Nutrition > Theory to practice - Stomach upsets, sports drinks and team sports
Theory to practice - Stomach upsets, sports drinks and team sports
Issue: Volume 28 Number 1
Background
Coaches and athletes are often faced with having to cope with stomach upsets during training or competition. Sports science has given us the common ways to prevent these: do not eat unfamiliar or large meals within 90–120 minutes of competing, avoid high-sugar drinks such as soft drinks beforehand, avoid drinks or food containing the sugar fructose such as fruit and fruit juices close to events or training and avoid large volumes of fluid before playing. However, recent research has examined the effects of different sports drinks on stomach upsets, and found that some drinks are more prone to causing players stomach upsets than others.
Research
The American study investigated whether different sports drinks’ carbohydrate concentration and osmolality (number of particles in solution) would provoke stomach upsets during intermittent, high-intensity exercise such as that seen within team sports in which athletes sprint, jog, walk and stand still at different times. Eighteen male and female adult (37 ± 1.9 years) and eighteen adolescent (17 ± 0.0 years) athletes were tested on separate days in a double-blind (athletes or scientists did not know who was taking what) and randomised (any order of taking drinks) trial of 6 per cent (6 grams of carbohydrate per 100ml common in most sports drinks) and 8 per cent (8 grams of carbohydrate per 100ml common in a few sports drinks) carbohydrate–electrolyte drinks immediately before and during each break between four 12-minute quarters of circuit training that included intermittent sprints, lateral hops, shuttle runs, and vertical jumps. Volumes of drinks were based on the body weight of each athlete and within volumes recommended by sports science. Stomach discomfort and fatigue surveys were completed before the first quarter and immediately after each of the four exercise quarters.
Findings
All ratings of stomach discomfort were modest throughout the study and increased throughout the four quarters. The overall index for gut discomfort, however, was greater for the 8 per cent sports drink than for the 6 per cent drink at quarters three and four. Averaging across all four quarters, the 8 per cent sports drink produced significantly higher mean ratings of stomach upset and side ache.
Coaches’ takeout
This study strongly suggests that coaches and athletes involved with intermittent-type sports (most team sports, tennis) should avoid the higher carbohydrate concentration and osmolality drinks if they want to help avoid stomach upset and side ache. Coaches and athletes are encouraged to check the ingredients of sports drinks and look under the ‘per 100ml column to see how many grams of carbohydrate are within each drink and look for the ones with 6g/100ml. If the sports drink contains higher than 6/100ml of carbohydrate, they might encourage their athletes to dilute the drink slightly by adding small amounts of water.
Reference
Shi X, Horn MK, Osterberg KL, Stofan JR, Zachwieja JJ, Horswill CA, Passe DH and Murray R 2004, ‘ Gastrointestinal discomfort during intermittent high-intensity exercise: effect of carbohydrate-electrolyte beverage’, International Journal of Sport, Nutrition, Exercise and Metab olism , 14(6):673–83 .
