Which nutrient serves as the most efficient fuel source for high-intensity, short-duration exercise?

Carbohydrates are the most efficient fuel source for high-intensity, short-duration exercise due to their capacity for rapid energy production. During such exercise, the body primarily relies on anaerobic metabolism, which utilizes carbohydrates stored in the muscles and liver as glycogen. This process can quickly produce adenosine triphosphate (ATP), the energy currency of the cell, providing the necessary fuel for explosive movements, such as sprinting or heavy lifting.

The efficiency of carbohydrates in this context is further demonstrated by their ability to support high-intensity efforts, where rapid energy release is crucial. Unlike fats, which are metabolized more slowly and are better suited for prolonged, lower-intensity activities, carbohydrates can be broken down quickly through glycolysis. This swift conversion allows for sustained efforts in activities such as intermittent sprints, circuit training, or high-intensity interval training.

Proteins, while essential for muscle repair and growth, are not a primary energy source during exercise unless carbohydrate stores are depleted, making them less suited for immediate energy needs. Vitamins do not provide energy but play supportive roles in metabolic processes. Therefore, carbohydrates are clearly the preferred and most effective fuel source during high-intensity, short-duration exercise.