How does expired ventilation behave as exercise intensity increases?

As exercise intensity increases, expired ventilation increases in a linear fashion. This phenomenon occurs because, during physical activity, the body's demand for oxygen rises significantly, and as a result, the respiratory system responds by increasing the volume of air exhaled per minute.

The linear increase in expired ventilation occurs primarily due to the need to eliminate carbon dioxide produced during metabolism and to provide adequate oxygen to the working muscles. The relationship between exercise intensity and ventilation shows that as the workload increases, more air must be breathed in and out to meet these metabolic demands.

This understanding is fundamental in assessing exercise performance and overall cardiorespiratory fitness, as knowing how ventilation changes with intensity helps in designing optimal training programs and understanding physiological responses to exercise.