High-intensity interval training (HIIT) involves alternating periods of intense exercise with short recovery intervals. This training method aims to boost cardiovascular fitness and increase metabolic rate in a shorter duration. HIIT workouts can include various exercises, such as sprints, cycling, or bodyweight movements. The intensity level is typically near maximum for short bursts, followed by brief rest periods. This technique enhances endurance and strength and can effectively promote fat loss, making it a popular choice in fitness routines.