High-intensity interval training (HIIT) benefits cardiovascular fitness by incorporating alternating periods of intense effort with lower-intensity recovery phases. This method enhances the heart's efficiency, improving its ability to pump blood and deliver oxygen to muscles. HIIT also leads to greater caloric expenditure in shorter time frames compared to steady-state exercise, promoting improved metabolic health. Additionally, studies indicate that HIIT can significantly improve VO2 max, a key indicator of cardiovascular fitness. Because of these advantages, HIIT is an effective workout choice for those looking to boost their heart health and overall endurance.