The type of fuel used during exercise primarily depends on its duration and intensity. During short, high-intensity exercises, the body predominantly utilizes carbohydrates stored as glycogen for quick energy. As exercise duration extends, particularly during moderate to low-intensity efforts, the body transitions to using fat stores as a primary energy source. This shift allows for sustained energy release during extended activities. Understanding these fuel sources is crucial for optimizing nutrition before, during, and after exercise to enhance performance and recovery.

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