What is the primary source of energy for intense exercise?

The primary source of energy for intense exercise is carbohydrates. During high-intensity activities, the body relies heavily on carbohydrates because they can be quickly converted into glucose, which is then used for energy. This process is crucial for activities that require quick bursts of energy, such as sprinting or weightlifting, where the demand for fuel is immediate and substantial.

Carbohydrates stored in the muscles as glycogen can be rapidly mobilized to meet the energy needs during these intense workouts. In contrast, fats and proteins are utilized more in lower-intensity activities or during prolonged endurance exercises. Fats, while they provide a significant source of energy during longer, less intense periods of exercise, do not supply the rapid energy needed for high-intensity activities. Proteins primarily serve as building blocks for tissue repair and are not a primary energy source during exercise. Vitamins also do not provide energy but are necessary for various metabolic processes that support energy production.

Therefore, carbohydrates are essential for sustaining quick energy needs during intense physical activity, making them the most effective and efficient source of energy in this context.