All my research in sports nutrition indicates that ingesting carbohydrate sports drinks, e.g., Gatorade and Powerade (not energy drinks that contain caffeine or other supplements), within 15-30 minutes of exercise lasting >60-90 minutes helps to maintain energy and replenish the athlete’s glycogen stores. Yet I routinely encounter swim coaches who recommend against these drinks on the grounds that they will cause stomach upset, increase thirst, and result in dehydration. I concur that these beverages may be upsetting to the stomach but feel it is important to replace electrolytes and glucose in those who are exercising strenuously. Your comments, please.
—Mitzi C. Amelon, DO, West Bloomfield, Mich.
In an effort to combat the often fatal dehydration caused by diarrheal illness, the World Health Organization (WHO), in 2002, issued a recommendation that oral rehydration solutions contain the following composition to maximally absorb water via the small-bowel sodium-glucose co-transport system: 2.6 g sodium chloride, 2.9 g trisodium citrate, 1.5 g potassium chloride, and 13.5 g glucose, all per liter of water (www.afro.who.int/cah/documents/intervention/acute_diarrhoea_joint_statement.pdf. Accessed August 13, 2008). Gatorade contains significantly more carbohydrate (approximately 60 g/L) and much less sodium (464 mg/L) than the recommended WHO formulation and thus is not optimal to treat severe dehydration. However, good research (much of it sponsored by Gatorade) supports usefulness of Gatorade in the prevention of excessive fluid loss from physical activity, and there is no evidence to suggest that it can actually precipitate dehydration. Additionally, a recent study showed that the ingestion of sodium-free fluids (such as water) to replace sweat losses during intense exercise can lead to hyponatremia and decreased exercise performance compared with sodium-containing sports drinks, such as Gatorade (J Appl Physiol. 2006;100:1433-1434). Not everyone will like the flavor of such sports drinks, and exercising with a full stomach can lead to stomach upset, but drinks such as Gatorade are otherwise perfectly appropriate for “sweat replacement” and maintenance of hydration in a healthy athlete.
—Daniel G. Tobin, MD (119-12)