What is the main stimulus for increasing pulmonary ventilation during aerobic exercise?

The primary stimulus for increasing pulmonary ventilation during aerobic exercise is the increased production of carbon dioxide (CO2) by the body's working muscles.

As the intensity of exercise increases, so does the metabolic rate of the muscles, leading to greater CO2 production.

This increase in CO2 levels triggers the respiratory control centers in the brain, particularly the medulla oblongata, to initiate a compensatory response by increasing the rate and depth of breathing. This ensures that the excess CO2 is efficiently eliminated from the body and the blood's pH is maintained within a narrow optimal range.