The physiological effects of high-intensity interval training (HIIT) include increased metabolic rate, improved cardiovascular fitness, and enhanced fat loss. HIIT alternates short bursts of intense exercise with periods of rest or lower-intensity activity, promoting greater calorie burn in a shorter time. This type of training can lead to adaptations in both aerobic and anaerobic systems, increasing stamina and strength. Additionally, research suggests that HIIT can improve insulin sensitivity and glucose metabolism, reducing the risk of chronic diseases. Overall, HIIT provides efficient and effective workouts for diverse fitness levels.