The term "HIIT" stands for High-Intensity Interval Training. This workout format involves alternating short bursts of intense exercise with periods of rest or lower-intensity exercise. HIIT effectively improves cardiovascular fitness, burns calories, and builds endurance in a shorter timeframe than traditional steady-state workouts. It can be customized with various exercises (e.g., sprinting, cycling, or bodyweight movements) to suit individual fitness levels and preferences. The efficiency and versatility of HIIT have contributed to its growing popularity in fitness and workout regimes across the globe.