High-intensity training, such as HIIT, significantly impacts cardiovascular fitness by improving heart efficiency and increasing VO2 max, which is the maximum amount of oxygen the body can utilize during intense exercise. This training method challenges the cardiovascular system and promotes adaptations that lead to better oxygen delivery throughout the body. Regular participation in high-intensity workouts also supports fat loss and improves metabolic function, further enhancing cardiovascular health. Consistency in such training can lower the risk of developing heart disease and improve overall physical performance, contributing to a healthier lifestyle.