Sports drinks

Sports drinks contain water, sugars and electrolytes, usually sodium, chloride and potassium.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.} USA Triathlon says carbohydrate plus sodium is absorbed more quickly than water alone, making these drinks useful for sessions longer than 60 minutes.^{2USA Triathlon, Complete Triathlon Guide, p. 323.} The NSCA puts the benefit at aerobic endurance work beyond 60 to 90 minutes.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.}

In practice

• For clients training for general health or weight loss, the carbohydrate benefit may be small and the extra calories unwelcome.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.}
• A sports drink alone won’t match carbohydrate use during prolonged, intense exercise unless the client drinks an excessive amount.^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 222.} The NSCA suggests 30 to 90 g of mixed carbohydrates per hour for aerobic endurance athletes during prolonged activity.^{4Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 225.}
• During intense exercise or sessions lasting hours, heavy intake of plain water or low-sodium drinks can dilute blood sodium to dangerous levels.^{5Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 214.} Fluid intake shouldn’t exceed sweat loss, and sodium should come from drinks or food.^{5Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 214.}
• Sodium helps stimulate thirst, while carbohydrate supplies energy.^{6International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 508.}

Carbohydrate and electrolyte concentrations

For prolonged activity in hot weather, the NSCA strength and conditioning text, citing the Institute of Medicine, and IPTA call for 20 to 30 mEq of sodium and 2 to 5 mEq of potassium per liter, with 5% to 10% carbohydrate.^{5Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 214.},^{6International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 508.} The NSCA personal training text says commercial drinks contain 6% to 8% carbohydrate.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.} USA Triathlon puts the optimum at 5% to 8% carbohydrate and 10 to 30 millimoles of sodium per liter.^{2USA Triathlon, Complete Triathlon Guide, p. 323.}