Every now and then I hear about something that truly astounds me. Today I read that most people only breathe out of a single nostril at a time, and that nostrils take turns being the dominant, breathing nostrils, switching every 90 minutes to four hours. At first I thought this sounded like nonsense, another bit of internet misinformation. But I checked and, sure enough, I was only using one nostril. I googled and it seems to be a medical fact.