The effect of high-intensity interval training (HIIT) on cardiovascular health is significantly beneficial. HIIT involves alternating short bursts of intense activity with periods of rest or low-intensity exercise. This training method enhances cardiovascular fitness by improving heart efficiency, lowering blood pressure, and boosting overall endurance. Studies have shown that HIIT can also lead to significant improvements in aerobic and anaerobic performance, making it a time-efficient workout option for improving heart health.