Fat serves as a significant energy source during prolonged exercise when carbohydrate stores become depleted. The body oxidizes fatty acids to produce ATP, the energy currency needed for muscle contraction. This metabolic shift typically occurs after about 20 minutes of steady aerobic activity. Maintaining low intensity during exercise allows the body to utilize fat more efficiently, promoting endurance and assisting in overall fat loss. Thus, integrating longer sessions of aerobic workouts can enhance fat oxidation and improve performance.