 If you think about it, it makes sense. The more air that passes through your nasal passages, the more it sucks the moisture out of the mucous membranes, the more the mucous membranes shrink back, which increases the air capacity. So the more air you breathe through your nose, you have a greater capacity to breathe air through your nose. There's a guy, I don't know if you remember, his name was James Nestor. He teaches athletes, even under heavy exertion,