High-Intensity Interval Training, commonly known as HIIT, is a form of cardiovascular exercise that combines short periods of intense, almost maximal effort with shorter periods of low-intensity recovery or rest. The premise of HIIT is to push the body to its limit during the high-intensity intervals, effectively increasing the heart rate and causing the body to require more oxygen during the recovery phase. This process, often referred to as the ‘afterburn effect’ or ‘Excess Post-exercise Oxygen Consumption’ (EPOC), leads to a greater total calorie burn, making HIIT a highly efficient way to improve cardiovascular fitness and enhance fat loss. HIIT can incorporate a variety of exercises including bodyweight movements, weightlifting, and cardio modalities, and can be adapted to suit a wide range of fitness levels and goals.