The difference between aerobic and anaerobic exercise lies primarily in how the body generates energy during physical activity. Aerobic exercise, such as running or swimming, relies on oxygen to sustain prolonged activity, focusing on endurance and cardiovascular fitness. In contrast, anaerobic exercise, like weightlifting or sprinting, occurs in short bursts where oxygen demand exceeds supply, emphasizing strength and power. Both forms of exercise are essential for overall fitness, with aerobic activities improving heart health, while anaerobic exercises enhance muscle strength and size.