True or False? Low-intensity exercise is primarily sustained by glycogen breakdown, while high-intensity exercise is primarily sustained by lipid metabolism.

The correct answer is based on the metabolic pathways utilized by the body during different intensities of exercise. During low-intensity exercise, the body predominantly uses lipid metabolism as the primary source of energy. This is because fats are more efficiently metabolized in a steady-state, lower-intensity effort, where oxygen is sufficiently available for the breakdown of fatty acids.

Conversely, high-intensity exercise primarily relies on glycogen breakdown. At higher intensities, the body requires quick access to energy, and glycogen stored in muscles is more readily available for immediate use compared to fat, which takes longer to mobilize and metabolize for energy during intense activities.

Understanding these energy systems is essential for optimizing training and performance, as it influences how nutrition and exercise regimens may be designed for individuals based on their goals.