Differences in energy expenditure among exercise types include variations in intensity, duration, and the nature of the movements involved. Aerobic exercises, such as running or cycling, generally burn more calories over extended periods due to sustained heart rate elevation. In contrast, anaerobic exercises like weightlifting promote muscle growth and metabolism but may burn fewer calories during the activity. High-intensity interval training (HIIT) can lead to increased calorie burn even after the workout, known as the afterburn effect. Understanding these differences can help individuals tailor their workout routines to meet specific fitness goals.