Dietary macronutrient recommendations for optimal recovery post-exercise: Part I

Prolonged, strenuous exercise results in muscle glycogen depletion. Recovery of these stores prior to the next training session or competition is crucial to optimise exercise performance. Nutrition plays an important role during the post-exercise recovery period when processes such as muscle regeneration, glycogen and fluid restoration take place. By manipulating the timing, type and frequency of food intake the rate of recovery can be enhanced, which is of particular importance to athletes performing multiple training or competition sessions within a day, or on a dayto-day basis and recovery time is limited. Restoration of muscle glycogen stores is especially important for athletes participating in prolonged exercise, since depleted glycogen stores are associated with impaired exercise performance. Key factors affecting muscle glycogen storage are carbohydrate (CHO) availability and an increased insulin concentration, both of which are influenced by amount and timing of CHO intake, type of CHO ingested, the ratio of CHO to protein ingested, and the fat content of a food item or meal. To maximise the rate of muscle glycogen restoration during a short (< 6-hour) recovery period, 1 - 1.5 g moderate to high glycaemic index CHO/kg body weight (BW) immediately post-exercise, followed by 0.8 - 1.5 g moderate to high glycaemic index CHO/kg BW/hour (divided in smaller doses every 15 - 60 minutes) for 3 - 4 hours should be ingested. With a longer recovery period (≥ 6 hours) muscle glycogen storage is independent of type of CHO ingested but a total of 7 - 10 g CHO/kg BW should be taken in within a 24-hour period. Combining protein with an adequate amount of CHO (> 1 g/kg BW/hour) has no added advantage in terms of enhanced rate of glycogen storage, but can be of practical importance. Additionally, this combination may be beneficial since CHO and amino acid availability are important for muscle repair during the recovery period, as will be discussed in detail in Part II of this article