How To Breathe Properly | Brian Mackenzie | Modern Wisdom Podcast 121
Brian Mackenzie (guest), Chris Williamson (host), Narrator
In this episode of Modern Wisdom, featuring Brian Mackenzie and Chris Williamson, How To Breathe Properly | Brian Mackenzie | Modern Wisdom Podcast 121 explores transform Your Physiology and Performance Through Simple, Intentional Breathing Practices Chris Williamson and breathwork expert Brian Mackenzie explore how breathing mechanics and chemistry underpin virtually all aspects of human physiology, from energy production and nervous system balance to cognition and movement.
Transform Your Physiology and Performance Through Simple, Intentional Breathing Practices
Chris Williamson and breathwork expert Brian Mackenzie explore how breathing mechanics and chemistry underpin virtually all aspects of human physiology, from energy production and nervous system balance to cognition and movement.
Mackenzie explains the primacy of aerobic metabolism and carbon dioxide tolerance, arguing that most people live in an unnecessarily stressed, anaerobic state due to poor breathing patterns and chronic mouth breathing.
They discuss nasal breathing as the body’s built‑in ‘training mask,’ how breath controls heart rate, digestion, and emotional state, and why breath is the foundational lever for human performance and recovery.
The conversation closes with practical recommendations: simple CO₂ tolerance testing, daily breath protocols (via Mackenzie’s State app), and periods of nasal‑only training to rewire physiology and improve both health and athletic output.
Key Takeaways
Prioritize nasal breathing to stay more aerobic and less stressed.
Breathing through the nose naturally limits airflow, engages the diaphragm, humidifies and filters air, and keeps you in a more efficient aerobic state; chronic mouth breathing accelerates sympathetic activation and pushes you toward unnecessary anaerobic metabolism.
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Use a CO₂ tolerance test as your ‘breath MOT.’
A simple max exhale test after a few controlled breaths can reveal mechanical diaphragm control, physiological CO₂ tolerance, and your reactivity under stress; times under ~20 seconds indicate a highly reactive, overcooked system that needs down-regulation and recovery.
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Train your breath daily, just like you train your body.
Adding 5-minute breath protocols in the morning (to focus/activate) and evening (to downshift for sleep) can improve HRV, sleep quality, CO₂ tolerance, and emotional regulation; apps like State personalize rhythms based on your responses rather than using one-size-fits-all methods.
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Dedicate 3–4 weeks to nasal-only training when possible.
Temporarily performing all training with the mouth closed forces your physiology to become more aerobically efficient, lowers unnecessary stress load, and can unlock better performance for strength, power, and endurance athletes once the adaptation period passes.
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Use breath to consciously modulate heart rate and state.
You can’t will your heart rate to change directly, but you can reliably lower it and shift nervous system balance through longer, controlled exhales and slower breathing; this is the fastest lever for transitioning between ‘on’ (sympathetic) and ‘rest/digest’ (parasympathetic).
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View CO₂ as a useful stress signal, not just ‘waste.’
Carbon dioxide is the body’s metabolic stress messenger and gatekeeper for oxygen utilization; improving CO₂ tolerance (rather than always offloading it quickly) enhances oxygen efficiency, resilience to stress, and cognitive stability under load.
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Let breath guide the purpose of your training, not ego.
Mackenzie argues that the true purpose of training is to make better decisions under stress; when workouts become about ‘winning’ the drill instead of feeling and learning from physiological signals (like breath struggle), you lose the deeper adaptive value.
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Notable Quotes
“The mind is the king of the senses, but the breath is the king of the mind.”
— B.K.S. Iyengar (quoted by Brian Mackenzie)
“All chemistry in the body is regulated through our breath.”
— Brian Mackenzie
“Carbon dioxide is the metabolic stress messenger of the human body.”
— Brian Mackenzie
“Any human being that does not have a movement practice is not being a human being.”
— Brian Mackenzie
“All training, at the foundation of training, is to make better decisions under stress.”
— Brian Mackenzie
Questions Answered in This Episode
How would my performance and recovery change if I spent a month doing all my training with nasal-only breathing?
Chris Williamson and breathwork expert Brian Mackenzie explore how breathing mechanics and chemistry underpin virtually all aspects of human physiology, from energy production and nervous system balance to cognition and movement.
Get the full analysis with uListen AI
What does my current CO₂ tolerance test result reveal about my stress levels, recovery status, and emotional reactivity?
Mackenzie explains the primacy of aerobic metabolism and carbon dioxide tolerance, arguing that most people live in an unnecessarily stressed, anaerobic state due to poor breathing patterns and chronic mouth breathing.
Get the full analysis with uListen AI
In which daily situations (work, sleep, conversations, training) am I unconsciously mouth-breathing, and what does that say about my nervous system state?
They discuss nasal breathing as the body’s built‑in ‘training mask,’ how breath controls heart rate, digestion, and emotional state, and why breath is the foundational lever for human performance and recovery.
Get the full analysis with uListen AI
How can I integrate breath control and visual focus together to improve my decision-making in genuinely high-stakes or high-pressure moments?
The conversation closes with practical recommendations: simple CO₂ tolerance testing, daily breath protocols (via Mackenzie’s State app), and periods of nasal‑only training to rewire physiology and improve both health and athletic output.
Get the full analysis with uListen AI
If the real purpose of training is better decisions under stress, how should I redesign my workouts to prioritize awareness of breath over chasing numbers or ‘wins’?
Get the full analysis with uListen AI
Transcript Preview
Today, 500 million years ago, aerobic metabolism sits at the forefront of the most efficient way to use energy. And so anything outside of aerobic metabolism becomes anaerobic. So if I don't have that process, that conversion of energy, I'll default very simply, and we should, to this higher stress situation of using energy. So anaerobic doesn't necessarily become a training process. It's more or less the byproduct of I'm no longer able to handle aerobically what's going on.
Mm-hmm.
So how quickly I can come back to that aerobic is literally how f- well I can. So w- having a very high aerobic capacity (laughs) means I function high aerobically. So when we look at people like a guy smashing the two-hour marathon, what does he look like physiologically? And although there's like ... Look, uh, to be totally hon- Like, look, I support and I'm very happy for the man and everything, but realistically, if he were in the same setup as they were in 1950 or even 1980, he wouldn't have run a sub two-hour marathon.
I'm joined by Bryan Mackenzie, the man behind Power Speed Endurance, and today we are talking about something that you will all be familiar with, but probably doing a little bit wrong: breathing. Bryan, welcome to the show.
(laughs) Thanks for having me.
It's gonna be awesome. I'm really excited to speak about this sort of stuff today. We've been talking about endurance a lot recently. Had Alex Hutchinson, writer for Runner's World, on analyzing Eliud Kipchoge's recent performance. We've had the, uh, Bryan Carroll, uh, from, uh, PowerAct Strength on talking about squatting at over 1,000 pounds, and all of this is enabled by a lot of different things. But I guess principally, one of those is breath work, right?
Yeah. Well, physiology and, I mean, all chemistry is regulated through our breath. So (laughs) anything and everything. I mean, I- I'm, uh ... I- I've known Alex for quite some time. We've kind of gone, we've gone back and forth over the years. He's a great ... He's a fucking s- kid, man. I like him a lot. Um, I don't know your other, the other guy, but to squat 1,000 pounds is to understand some things.
(laughs) He really does.
(laughs)
He really does understand some things. I mean, m- uh, Kelly Starrett, w- we just released a- an episode with him today. We've had Dr. Stu McGill on.
Yep.
So, you know, we've had a lot of these guys.
Mm-hmm.
And when they, when they talk about this, even, you know, Kelly and, and Stu, people that are really, really kind of at the, uh, the, the top of their game, very well respected within their fields, it's rare that I hear someone bring up breath work.
(sniffs)
D- why do you think that is?
Did Kelly?
Kelly didn't. Kelly didn't, no. We were talking a bit about The Game Changers.
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