eli5 how does the nasal cycle work?


I understand what it is, buy what is “blocking” the airway? Is the inside of your nose shrinking? I can’t find a straight answer.

In: 3

It’s just mucus, your hypothalamus activates half of your autonomic nervous system which causes mucus secretion and build up in one nostril while leaving the other clear.

Your nose goes through a cycle, dude! Left nostril, right nostril, taking turns being blocked (not entirely, just around 70% or so). The septum swells on one side, reducing airflow. Then, it’s a tag team – the swelling subsides and the other nostril gets the ‘swell’ treatment. No shrinking, just good ol’ ebb and flow.

Parts of your nose are filled with erectile tissue not dissimilar from that found in the penis or clitoris. This can cause the airway on one or the other side of the nose to become narrower as the tissue, which is in the wall of the airway, becomes engorged with blood

For reasons that are unclear, your body alternatively fills the tissue on one side of your nose, constricting airflow through that nostril. Which nostril is constricted and which is clear alternates, usually with a period of 1-6 hours.

Note that it’s physiologically possible for both or neither nostril to be constricted at the same time, though normally precisely one is at any time. Being congested in both nostrils at the same time is typically from excess mucus production (due to disease or allergy), not from simultaneous contraction via the erectile tissue, though when you experience that you can breathe through only one nostril, it’s usually because of this – you have the same mucus on both sides but a wider pipe on one, so it isn’t blocked.