Dear shgadwa, As with many habits it takes work to break it. I have many patients who have been unable to breathe for most of their lifetime through their noses and then have surgery and can breathe fine and will discover themselves mouth breathing on occasions. Most patients overcome this quickly once learning the comforts of breathing through their nose. With constant reminders to yourself and really thinking about your breathing you can change your current patterns. Many patients who are singers, athletes, yoga instructors work hard to learn to breathe in different ways as well to better achieve their needs. With a little time and effort you should be breathing fine through your nose. Best regards, Michael V. Elam, M.D.
That is great that now you can breathe through your nose! As you suggested, you've developed a habit of breathing through your mouth because of your inability to breathe through the nose previously. Other than consciously telling yourself to close your mouth to breathe through your nose, I don't think there is a way. I think if you keep doing that, eventually over a period of time, you will develop a new habit of breathing through your nose. Good luck!