Nutrition for Endurance Athletes

A well-balanced, adequate dietary intake is essential for both health and athletic performance. Compared to sedentary subjects endurance athletes have higher energy demands and subsequently higher macronutrient requirements. Especially carbohydrate requirement is higher than in non-active individuals (approx. 3.5g/kg/d) to ensure energy availability during exercise and to replenish glycogen stores after exercise. During weeks of moderately intense exercise a carbohydrate intake of 5-7 g/kg/d is recommended. Glycogen synthesis follows a biphasic manner with an insulin-independent rapid synthesis rate during early regeneration and an insulin-dependent slow synthesis rate in the later regeneration period. Therefore, elite athletes should ingest 1.2-1.5 g/kg/h of carbohydrates with a moderate to high glycemic index immediately after exercise. In some cases high carbohydrate intake may result in a conflict with sports specific requirement of a low body weight. However, a minimum of 5% body fat for male and 12% for female athletes is recommended to avoid health issues. During endurance exercise an adequate fluid and electrolyte intake is essential to prevent both dehydration and exercise-induced hyponatremia. Fluid replacement recommendations should be assessed on an individual basis by considering exercise intensity and duration, temperature, sex and body weight. For each hour of exercise the consumption of 400-800 ml containing a minimum of 450 mg sodium per litre is recommended.