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 pm-exercise levels. It is followed by 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, which requires intake of carbohydrates. To facilitate rehydration, carbohydrates should be ingested as 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.