Aerobic activity requires oxygen to produce energy, whereas anaerobic activity occurs in the absence of oxygen. During aerobic exercise, such as running or cycling, the body efficiently uses oxygen to convert glucose into energy, supporting sustained physical performance. In contrast, anaerobic activities, like sprinting or weightlifting, rely on energy sources through processes like glycolysis, producing energy quickly but also leading to lactic acid buildup. Understanding these differences is essential for optimizing training regimens and energy utilization during different forms of exercise.