11 Differences Between Swimming and Gym Workouts That Impact Weight Loss

5. Intensity control and interval training: hitting the burn zones

Exercise intensity shapes calorie burn, hormonal response, and fat-loss efficiency. In the gym, intensity is simple to measure and manipulate—you set treadmill speed, interval durations, and resistance levels. High-intensity interval training (HIIT) on a bike or treadmill is well studied and reliably increases post-exercise oxygen consumption and fat metabolism for hours after the workout.