The Nasal-Only Breathing Reset
Spend three to four weeks nose-only to rewire your physiology back to aerobic
- Difficulty
- Moderate
- Time to result
- ~weeks to results
- Steps
- 5
- Confidence
- 74%
The nasal-only reset uses the nose as the body's native training mask to pull an athlete out of chronic mouth-breathing and back toward aerobic function. It pairs two short daily breath protocols — one in the morning for alertness, one in the evening for sleep — with a block of three to four weeks of strictly nasal-only breathing applied across all training. Because the nose restricts fast air, it forces the diaphragm to work harder and keeps respiration in the aerobic, parasympathetic-leaning zone; opening the mouth blows off carbon dioxide, shifts you sympathetic, and burns less fat. The hard part is ego: nose-only forces most athletes to drop intensity, which feels like a demotion. Mackenzie says adaptation lands at roughly three weeks, after which physiology is measurably rewired and the athlete can do things they previously couldn't. The window should be avoided only when a priority event is imminent.
Origin
Emerged from Brian Mackenzie's Art of Breath and Power Speed Endurance programs after a training mask led him to realise the nose already does that job, informed by George Catlin's 1800s observation that indigenous cultures never breathed through their mouths.
Core principles
- 01The nose is a built-in training mask — it filters, humidifies, and forces the diaphragm to pull
- 02Nasal breathing keeps you aerobic; opening the mouth tips you toward anaerobic and sympathetic
- 03Backing off intensity long enough lets physiology rewire, roughly three weeks
- 04Twice-daily breath protocols anchor the reset
- 05Ego resistance to slowing down is the main obstacle, not physical capacity
How to run it
- 1
Anchor two daily breath protocols
Do one breath protocol in the morning for alertness and one in the evening for sleep, roughly five minutes each. Run each for a few weeks and notice what improves and how you feel.
Pro tip Use the evening protocol within two hours of bed to downshift and improve deep and REM sleep.
- 2
Commit to a three-to-four-week nasal-only block
Dedicate three to four weeks to strictly nasal-only breathing. Do not go past the nose; if you have to open your mouth, you have exceeded your current aerobic capacity.
Pro tip This works across every methodology — MMA, powerlifting, CrossFit, endurance — not just runners.
Watch out Skip this block if you have an A-priority race, championship, or Olympic event within about two months.
- 3
Back off intensity to hold the seal
Reduce training intensity enough that you can keep breathing through your nose. The point is to let the physiology recalibrate, not to grind.
Pro tip Expect this to bruise the ego — for most trained athletes the forced slowdown is the real challenge.
Watch out Refusing to back off keeps you mouth-breathing and defeats the reset.
- 4
Let adaptation land at about three weeks
Hold the discipline for the full block. Adaptation to the new pattern arrives around three weeks, after which the rewiring becomes usable capacity.
- 5
Retest and confirm the rewiring
Re-run the CO2 tolerance test to verify the reset moved the number. Improvement confirms the physiology has shifted back toward aerobic efficiency.
Pro tip Pair breath protocols before meditation to amplify both practices.
In the wild
Mackenzie applied the nasal-only reset with athletes people would never expect to slow down, including CrossFit competitor Tia. The block rearranged what was going on physiologically and gave them abilities they didn't think they could manage, empowering rather than diminishing them despite the reduced intensity during the window.
→ Athletes who resisted the idea came out with expanded capacity and a rewired aerobic base after roughly three weeks.
Mackenzie studied video of Eliud Kipchoge frame by frame and observed he runs most of his marathon nose-only, with salt marks running down his nose and his mouth shut in most photographs. To Mackenzie this is the visible signature of an athlete whose physiology stays aerobic under extreme load — the endpoint of what nasal breathing trains.
→ A world-class endurance performance held together by nasal breathing, illustrating the ceiling the reset aims toward.
Common mistakes
Running the reset before a key event
The block temporarily lowers top-end intensity, so doing it within two months of an A-priority competition sacrifices peak performance when you need it.
Refusing to lower intensity
If ego keeps you pushing hard, you will be forced to mouth-breathe, which cancels the aerobic rewiring the block is designed to produce.
Skipping the daily protocols
The morning and evening breath protocols anchor the reset; dropping them leaves the nasal block without the practice that builds CO2 tolerance and downshifts the nervous system.
Is it for you?
Best for
Trained but overstimulated athletes across any discipline who are not peaking for a near-term competition and can afford weeks of reduced intensity.
Not ideal for
Athletes inside two months of a world championship, Olympic medal, or A-priority race who cannot sacrifice top-end intensity.
From the transcript
“there's no reason why you can't go dedicate 3 to 4 weeks to strictly nasal only breathing and take enough step back to actually get…”
“It's called a nose. And holy crap, it like it has this filter system. It's got these this humidification system.”
“for the first few weeks, we're going to just be nasal breathing. You can't go anything past nasal breathing.”
From the episode
How To Breathe Properly - Brian Mackenzie - #121
Brian Mackenzie