Nose breathing is more effective at increasing oxygen uptake than breathing through the mouth. When our nose is blocked, the oxygen uptake in the blood reduces. In a study of individuals who continuously breathe through their noses, arterial pressure of oxygen increased by nearly 10%.
Swift AC, Campbell IT, McKown TM. Oronasal obstruction, lung volumes, and arterial oxygenation. Lancet. 1988 Jan 16;1(8577):73-5. doi: 10.1016/s0140-6736(88)90282-6. PMID: 2891980.
Bartley, James, and Conroy Wong. “Nasal Pulmonary Interactions.” In Nasal Physiology and Pathophysiology of Nasal Disorders, pp. 559-566. Springer, Berlin, Heidelberg, 2013.
