The key difference between aerobic and anaerobic exercise lies in the presence of oxygen during the activity. Aerobic exercise, such as running, swimming, or cycling, relies on oxygen for energy, allowing for prolonged activities that enhance cardiovascular endurance. In contrast, anaerobic exercise includes high-intensity movements, like weightlifting or sprinting, that do not primarily depend on oxygen and result in shorter bursts of effort. Anaerobic activities build strength, speed, and muscle mass, while aerobic activities are effective for burning fat and improving stamina. Both types of exercise are crucial for balanced fitness.