When we train in Zone 2, we use oxygen to maintain a low-intensity cardio workout. Transporting oxygen throughout the body requires the coordinated functions of the heart, lungs, blood vessels, and blood.
The heart is our main pumping mechanism, distributing oxygenated blood throughout the body to working tissues. When the body begins to exercise, the heart has to pump more blood to meet this increased demand.
Stroke volume is the volume of blood pumped with each heartbeat. The heart pumps approximately 70 ml of blood per beat. Stroke volume and heart rate together determine cardiac output, which is the volume of blood pumped through the heart at a given time.
The effect of zone 2 training is that stroke volume increases while heart rate decreases during exercise, indicating increased cardiorespiratory endurance. This is the magic in the long run to slow things down in your training.
“The 2 cardio zone makes your heart stronger, and it will require fewer pumps to pump blood, making it more efficient,” Niren says. “Your body also expands your vascular system, which enables it to better deliver oxygenated blood to different parts of the body.”