High-intensity interval training (HIIT) differs from steady-state cardio primarily in its structure and intensity levels. HIIT alternates between short bursts of intense exercise (often exceeding 80% of maximum effort) and recovery periods, leading to improved cardiovascular fitness and calorie burn throughout the day. In contrast, steady-state cardio involves maintaining a consistent, moderate intensity for an extended duration. HIIT workouts are time-efficient and can enhance endurance and metabolic conditioning, while steady-state cardio is beneficial for endurance training and fat utilization. Both forms of exercise can be effectively integrated into a balanced fitness regimen.