Any physical activity, but especially intense exercise, requires a recovery period. After high performance activity, the body recovers in three distinct phases. Rapid recovery phase begins immediately after the exercise and lasts roughly 30 minutes. In this phase, the metabolic rate returns to pre-exercise levels. It is followed by an intermediate recovery phase, which lasts between 90 minutes to two hours. During this phase, the body begins to restore fluids by a process called rehydration. This is the most critical phase of recovery and requires intake of carbohydrates. To facilitate rehydration, carbohydrates should be ingested soon after an event or training session. Finally, in the longer phase of recovery, which can last from two to 20 hours, carbohydrate replenishment continues. It is during this longer phase of recovery that the damage done to the muscle by heavy exercise is repaired.
Just as both recovery and muscle repair are important, carbohydrate ingestion ensures that event fatigue does not set in. Training and post-exercise nutrition are essential for consistent performance, but to prevent and delay event fatigue carbohydrate replenishment is equally important. This replenishment , also called carbohydrate loading, is achieved by high carbohydrate consumption in the days immediately preceding the event. Carbohydrate loading helps athletes avoid "hitting the wall." Therefore, a high carbohydrate regimen yields greatest benefits for endurance athletes. These athletes include long-distance swimmers, cross-country skiers, soccer players, long-distance runners (especially marathoners),, triathletes and long-distance bicyclists. In general, carbohydrate replenishment is most effective for any athlete who participates in an event lasting more than 90 minutes.