I think that's a reference to the nasal cycle[1]. I notice it pretty commonly when sleeping, but during waking hours, esp. if I am exercising, both nostrils see

I think that's a reference to the nasal cycle[1]. I notice it pretty commonly when sleeping, but during waking hours, esp. if I am exercising, both nostrils seem to be unblocked. 1: https://en.wikipedia.org/wiki/Nasal_cycle https://en.wikipedia.org/wiki/Nasal_cycle