Say you go on a run, most likely by the end of this run you are panting and gasping for air. But what causes this unique phenomenon to occur? Is it because of a lack of oxygen or an excess of carbon dioxide?
While running or doing any form or exercise your body needs more oxygen, or specifically your blood needs more oxygen. Your blood pressure will rise as more oxygen enters your bloodstream, which thus means that this oxygen will increase the oxygen in your muscles. Because of all this, the oxygen in your lungs begins to decrease, which to conclude is why when you are gasping for air it is because of a lack of oxygen, not an excess of carbon dioxide.