Which fuel source is primarily used by the body during exercise?

The primary fuel source used by the body during exercise is glycogen. Glycogen is a form of stored carbohydrate found in the liver and muscles, and it can be rapidly broken down into glucose when energy is needed. During exercise, especially in high-intensity activities, the body primarily relies on glycogen to provide a quick and readily accessible source of energy.

Adenosine triphosphate (ATP) is crucial for muscle contractions and provides immediate energy for short bursts of activity, but it is not a fuel source that the body can sustain for extended periods. ATP is quickly depleted and must be regenerated from other sources. Therefore, while ATP is essential for initiating muscle movement, it cannot be considered the primary fuel source used during sustained physical activity.

Fatty acids are utilized during prolonged, lower-intensity exercise, but they are not the primary source of energy during high-intensity workouts where glycogen is favored due to its ability to generate ATP quickly.

Protein, while it can serve as an energy source in extreme circumstances (e.g., during long-duration exercise when glycogen stores are low), is not the primary fuel source for exercise. Instead, it plays a more significant role in muscle repair and recovery.

Understanding this hierarchy of energy sources helps