Comment by a9h74j

Yes, certainly for heavy congestion. However, for marginal cases, there might be some body adaptation made to help with efforts at nose breathing. .. Nestor avoids giving specific recommendations, given individual variations and needs. But the research seems to point to: there is a lot going on. For example, apparently the nose contains erectile tissue, perhaps helping explain how one can cycle between now one nostril being easier to breathe through, later the other. .. My very limited experience, living where I would usually call myself "always congested," is that given a little effort/intent at nose breathing, I now sense that my congestion is consistently less than before. (But N<1 as evidence, since there could be some seasonal change as well.)