Are the lungs and pulmonary ventilation a limiting factor in exercise?
I have touched on this question at various times, but I want to summarize here. The answer is clearly “Yes” for persons with pulmonary diseases. Also, ventilation can be limiting for persons with normal lungs who are in extreme environments (e.g., climbing Mount Everest without supplemental oxygen; high level of carbon monoxide in ambient air). For persons with normal lung function in normal, low-altitude environments, however, the answer to the question seems to be “No,” with one exception that I will note below. Following is a summary of some of the evidence. • Most important of all: Arterial PO2 remains at or near resting levels, so saturation of arterial blood with O2 remains close to 100%, even during exhaustive exercise. If pulmonary function were inadequate, significant arterial desaturation would be expected. • Maximal minute volume of ventilation during exhaustive exercise is still less than maximal voluntary ventilation. VE could increase even more during exercise, but it app
