Which one is better to breathe through (mouth or nose)?
your question is good, to have any filtering of air it is better to breathe out of your nose for lightly dusty conditions,on the other hand breathing out of your mouth is better to get lots of air into your lungs when your are engaging in sports,this depends on how cold it is if you are breating lots of cold air in the winter i.e. snowshoing x-counry sking,it is very important to know the temperature if are competing in a cold place it is better to breathe thru your nose the best you can.at the canada witer games last year some biatholon copetitons were cacelled.it was minus 35celsius .think of a turbo, better yet a blower, it blows more air into the engine and thus making the car go faster, same goes for geting air to all the working muscles you get more air by breathing thru your mouth the biggest and best path of least resistance wind pipe of your esphagas.
