No. Almost everyone will need to mouth breath while at max effort. It may be beneficial to deliberately nose-breath as long as possible, especially at Zone2.

No. Almost everyone will need to mouth breath while at max effort. It may be beneficial to deliberately nose-breath as long as possible, especially at Zone2. I try to transition to nose-in, mouth-out as a fallback before going mouth-in, mouth-out. Honestly, I don't even know how big of an effect it has, but I've been trying it for the past year to test it out. Been training for over a decade so I just enjoy testing new things.