High-intensity interval training (HIIT) benefits cardiovascular fitness by challenging the heart with bursts of intense exercise. This training method improves heart health by increasing cardiac output and optimizing the efficiency of the cardiovascular system. HIIT encourages greater oxygen uptake and ultimately leads to enhanced endurance and stamina. Regularly incorporating HIIT into a fitness regimen can lower resting heart rate and improve blood pressure levels. This type of training often results in quicker adaptations in cardiovascular fitness compared to steady-state exercises, making it effective for improving heart health.