At which exercise intensity is cardiac output likely to remain the same or slightly lower?

Cardiac output, which is the amount of blood the heart pumps per minute, typically increases with exercise intensity to meet the higher metabolic demands of working muscles. However, during submaximal exercise, which occurs at lower intensity levels, the body can efficiently manage its oxygen and nutrient delivery without a significant increase in cardiac output. In this phase, the body engages in more metabolic processes that can maintain performance without requiring a further increase in heart rate or stroke volume.

During maximal exercise, cardiac output reaches its peak as the body demands the utmost efficiency and effort. In the recovery phase, the body is returning to homeostasis, and cardiac output generally decreases from its peak levels, but this is a transitional state rather than a sustained exercise intensity. In high-intensity interval training (HIIT), the intervals push the heart rate and output significantly higher to accommodate intense bursts of activity.

Therefore, it is in submaximal exercise that cardiac output is likely to remain stable or potentially decrease slightly, as the demand is lower compared to maximal levels or intervals typical in high-intensity training.