If you really want to focus on building a tolerance to CO2 you have to ensure your mouth is closed most of the time.
Because of this I have had athletes ask if they too should tape their mouths while they workout. I’ve even heard trainers and athletes toss around the idea to hold water in their mouth while working out to keep them honest nose breathers. (This comes from an Apache initiation rite.)
My answer to these ideas is that you can hold yourself accountable. Even if you see a viral video of your favorite athlete working out with their mouth taped doesn’t make it necessary. When working out you should be present enough in what you are doing to recognize if you are breathing with your nose or mouth. To a large degree this is as important as nasal breathing. Focusing on your breathing has tremendous effects for your fitness. If you let tape do the job you likely won’t earn the same benefits.
There is a Time and Place
Like at night, while you are sleeping. Unlike working out, sleeping requires you to be unconscious. It is pretty hard to keep reminding yourself to close your mouth while you are asleep. That is why taping your mouth at night can do wonders. It keeps you honest when you can’t. It is important as well because if you do all that work to use your nose during the day and then at night mouth breathe you are undoing a lot of your gains.
You do not have to duct tape your whole mouth closed! A tiny strip of cloth tape over the middle of your lips does the job. If the idea of taping your mouth closed still freaks you out then check out this tape. It simply goes around your mouth using the elasticity to keep your mouth closed. Myotape
