Breathing is a rhythmic activity. Normally a person at rest makes approximately 16 to 17 respiratory incursions a minute. The rate is higher in infants and in states of excitation. It is lower in sleep and in depressed persons. The depth of the respiratory wave is another factor which varies with emotional states. Breathing becomes shallow when we are frightened or anxious. It deepens with relaxation, pleasure and sleep. But above all, it is the quality of the respiratory movements that determines whether breathing is pleasurable or not.
—Alexander Lowen, The Voice of the Body
A few months after Elee’s breath workshop, I journey to San Mateo, California, to the home of Brian Mackenzie, one of the world’s foremost experts on human endurance. I arrive at his architecturally unique bungalow. Inside I find a gym, his personal library, and more than a few strange experimental body-hacking devices—one of which looks a little like a miniature Tesla coil. There’s an assortment of high-end athletic gear in his garage-turned-weight room: stationary bikes, pull-up bars, road bikes and a dozen or so kettlebells (some molded into monkey faces and skulls), as well as a flag featuring the five interconnected Olympic rings. This unassuming skunkworks is actually a pilgrimage site. Each year, dozens of athletes and journalists seeking answers to the next fitness revolution come here to sit at the feet of the guru.
Mackenzie has authored several best-selling books on human endurance, and, depending on whom you talk to, is either a pariah of the fitness world or its savior. His most notable claim to fame is his insistence that short spurts of high-intensity workouts and breath regulation are a far better way to train for endurance events than the standard approach that requires building up increasingly long distances over weeks, months and years. He espouses a quality-over-quantity approach that examines the concept of endurance holistically. Though not its inventor, Mackenzie was ahead of the curve promoting HIIT. Many now take his word as gospel.
I take a seat on a long orange sofa and ask about the chest freezer brimming with icy water in his backyard. He tells me that the contraption has been the DIY solution for people who want to have access to an ice bath but live in areas where cold water is scarce. Every morning, Mackenzie takes a five-minute soak in his freezer and then warms up in his sauna. Later, when we jump into the heat together, we wear bell-shaped Russian banya hats made out of boiled wool to keep our heads cooler than our bodies. Mackenzie is the sort of guy who goes full-bore to chase any idea that might give him an edge in training the next crop of professional athletes. But he’s also constantly scrutinizing the results to track where he goes wrong.
One reason I’m here, of course, is to discuss how Mackenzie’s research taps into hidden reserves of human strength. I suspect that his breath routines and endurance protocols speak to what I’ve experienced with the Wedge. The other reason I’m here is that the last time I met him in person, Mackenzie had been using Wim Hof’s breathing method to give his athletes a boost on the field. I wrote about his training program in my earlier book about Hof. But recently he’s begun to turn away from Hof’s protocols. I want to know why.
…
But first, some Hof basics: One of the most stunning hacks offered by Hof’s method is that the same tweak that lets a person hold their breath for an exceedingly long time also makes them capable of brief spurts of incredible endurance. (You can find the exact protocol at the end of this book, along with other techniques from these chapters.)
A typical Wim Hof session revolves around three or four rounds of rapid controlled breaths followed by empty-lung breath holds—a variation of what I’d been doing in Lee’s class. The super-ventilation alters the ratio between carbon dioxide and oxygen, which tricks the body’s sensory system and pushes off the urge to gasp. It’s a physical wedge that creates space between stimulus and response. With each repetition, the breath holds lengthen until, for me, after the third round I hold for about three minutes. On the fourth round, you do something different. Instead of just holding your breath on the mat, you get up and start doing push-ups (or any other similar exercise) while holding your breath on an exhale. Most people discover that push-ups are much easier after hyperventilating. When I first tried the method, I doubled my push-ups after just one breathing session—going from 20 to 40 in a matter of minutes. After a few months, I worked my way up to occasionally hitting a breathless 80.
In the Wim Hof Method, the athletic boost comes from a well-understood pulmonary and circulatory hack. For reasons lost to evolution, our bodies can’t detect oxygen levels in the bloodstream, and instead only monitor the acidic byproduct of respiration—CO₂. When carbon dioxide concentrations hit a certain level, the brain broadcasts a panic signal urging you to stop physical activity, trigger a gasping reflex, or shut down entirely. Wim Hof’s hyperventilation techniques artificially lower CO₂ levels and trick the body into producing more physical output when it would ordinarily shut down. This is partially why I was able to hold my breath for so long in Elee’s class. It pushes you past your limits, a turbo boost—or as Mackenzie puts it, “It blows off the roof.” Another way to look at Hof’s method is to say that it works primarily on the sympathetic nervous system because the rapid breathing mimics the unconscious physiological effects of fight and flight. Over time, Hof’s protocols allow a person to take control of these unconscious stress processes and put them under conscious control. It seems like an athlete’s dream.
I’d seen the performance boost in my own training programs. I even have data. Before and after testing at a sports lab in Boulder, I showed staggering levels of improved endurance on something called a VO₂ max test. But I’ve never been an elite athlete, and Mackenzie was seeing something different with the people he worked with.
I turn on my recorder and repeat the question. “So why the shift?” I ask Mackenzie.
“With Wim’s method, when you blow off CO₂, it’s like taking the ceiling off your workout; the limits just sort of go away. But the catch is that it only works while you keep up with the breathing. I wanted my athletes’ physiologies to adapt long-term, but what we found is that while hyperventilation might give a person a personal record, it doesn’t allow them to reach new athletic peaks when they’re not doing the breathing,” he says.
When Mackenzie first heard about this strange performance boost, he reasoned that combining Hof’s hyperventilation and breath retention with HIIT programs would create long-term athletic gains in the coterie of athletes that he trained. When we first met a few years ago, I was struck by how much more power I had on a stationary bike as he took me through his protocols. But after publication and several more years of examining biomarkers, resistance training and competition results, Mackenzie started to back away from the program. Something was wrong, he says now. People were performing better in his gym, but the changes weren’t translating to success on the field.
Mackenzie realized that while controlling sympathetic activity is an important tool in a person’s kit, it’s only half the equation. He doesn’t just want to blow the roof off of physiology; he wants to raise the floor. If you think of the body as a car, the sympathetic responses kick in as it reaches the RPM red line. People don’t usually live on the edge of their capabilities; instead, most of our lives take place in a balanced place between fight and flight and rest and digest.
At a neurological level, sympathetic and parasympathetic impulses travel through the body on the two opposing branches of the vagus nerve, the twisted central conduit for most of our unconscious neural responses. Resting, it turns out, doesn’t mean simply lowering the volume of the nervous system; rather, it entails activating a different branch of the vagus nerve. While both sides of the vagus stay on in continual operation most of the time, one branch takes precedence over the other depending on the situation at hand. By controlling the floor and ceiling for athletic performance, Mackenzie is, in effect, training his athletes to consciously choose which branch of the vagus stays active. They’re training the way that their body reacts to stress, and over time, they wedge control over their vagus nerve.
Mackenzie wants to find a way to maintain a high level of physical activity in his athletes without relying on the sympathetic boost of adrenaline. In other words, he wants to maintain high parasympathetic “tone” during high-intensity workouts. And that means he needs to invert the paradigm and become the yin to Hof’s yang.
Of the thousands of breathing methods that exist, they all break down between those that ramp you up and those that bring you down. As a general rule, if you take more air in than you let out, you up-regulate your body, giving yourself an energy boost and heightened alertness. If you let out more air than you take in, you down-regulate, meaning you will relax and fall asleep easier. At a physiological level, down-regulation correlates with higher CO₂ levels in the blood and pulmonary system, and up-regulation means lower CO₂.
Mackenzie speculates that he didn’t see long-term changes in the athletes he trained with hyperventilation because they never adapted their bodies to operate with high CO₂ levels. They only learned how to boost their adrenaline.
But what would happen if a person conditioned their body to tolerate high CO₂ levels in their blood during high-intensity workouts and then used super-ventilation during competitions? Such a training program would both raise the tolerance floor and allow them to blow off the roof when they need an extra boost. Mackenzie’s protocols call for building up high loads of CO₂ in the bloodstream and then conditioning the body to get used to the discomfort.
Before I flew out to see him, Mackenzie asked me to figure out my own CO₂ tolerance. The instructions he sent were surprisingly simple. With a stopwatch in my hand, I took three full relaxed breaths, and then, on the fourth, a full inhale. Then I started the watch and began exhaling as slowly as possible. I was supposed to stop the timer when my exhale ended. This is more difficult than you might expect, and harder than a simple breath hold. When air leaves the lungs, CO₂ builds up in the blood, as do feelings of claustrophobia and panic. Since the exhale lowers the overall volume of air in the lungs, the CO₂’s signature is stronger than usual.
The second part of the test is a 28-point questionnaire that Mackenzie developed in conjunction with the Huberman Lab at Stanford to measure emotional reactivity. The self-assessment posits different ways that a person might react in stressful situations and asks subjects to rate their likely responses on a scale of one to four. At first the two components don’t seem interrelated. After all, how does measuring how long I can exhale determine how angry I get when someone cuts me off in traffic?
After testing more than 400 people in his protocols, Mackenzie says that physiological reactivity correlates strongly with emotional reactivity. Indeed, therapists who ascribe to cognitive behavioral therapy will sometimes use gas masks that deploy CO₂ in order to trigger panic attacks in a controlled setting as part of the therapeutic process. In CBT, the purpose of the training is to teach the patient that panic attacks aren’t as bad as they expect; in fact, it’s the anticipation that causes the most emotional pain. Mackenzie posits that there’s an added benefit to his training program: If you improve your CO₂ tolerance, you won’t just be a better athlete, but you are likely to be more emotionally stable, too, which translates to making better decisions on and off the athletic field.
Another way to look at this would be to go back to neural symbols that encode emotion and sensation together. If low CO₂ tolerance leads to pervasive feelings of anxiety, it would mean that if you can’t breathe correctly, every new symbol you generate has the physical sensations of anxiety baked into it.
Most people who come to Mackenzie can maintain their exhale for 20 to 40 seconds. When I try it, I make it to 72 seconds, which puts me in the advanced category. Most likely this is because of the amount of breathwork I’ve already done. I’m unusual, he says.
“Athletic prowess doesn’t predict good breathing,” he notes. “I meet pro footballers all the time who can’t exhale more than 20 seconds. We’re training the pulmonary system to work more efficiently. You can’t out-fitness breathing.”
The questionnaire backed up his prediction. With high CO₂ tolerance, I was also generally calm in stressful situations. This might explain how I’ve spent much of my career in stressful environments—the middle of war zones in India, the tops of African mountains, amid organ traffickers and Mafia bosses—without any post-traumatic symptoms that I’m aware of. Could it be that I’m naturally a good breather?
Certainly, much of the world isn’t very good at it. Mackenzie says that most people who don’t do breathwork are chronic over-breathers.
“Peek around your office some time and take a look at how people breathe,” he suggests. Most of us never learned to breathe right in the first place and, as is the case with our penchant for temperature comfort, put in the least amount of effort possible. “Most people breathe like this,” he says, and then starts taking shallow breaths through his mouth. It goes on for a few seconds, and he notes that it comes out to about 20 to 25 breaths every minute. Mindful breathers should be at around ten. Mackenzie says he averages about eight.
“Breathing is the brain’s remote control,” he says, letting the rest of the sentiment hang in the air. It’s the quintessential tool of the Wedge. Master breathing, and you can control your physiology.
Then he asks me if I’ve ever heard of George Catlin. Indeed I had; lately, Catlin has had a bit of a resurgence among a certain breed of biohackers who look to evolution for answers to human health. Born in 1796, Catlin was a renowned explorer, painter and ethnographer who spent much of his life traveling among indigenous tribes of North and South America. He traveled with William Clark (of Lewis and Clark) on explorations of the Missouri River and had the opportunity to meet tribes and communities who had never encountered white men before. Toward the end of his career, Catlin began to wonder why it was that nearly all of the tribes he encountered had incredibly low instances of chronic diseases. He claimed to have met “more than two millions of wild peoples” during his journeys and concluded that the secret to their health lay in two primary causes, which he described in one exasperatingly long run-on sentence.
“There is no animal in nature, excepting Man, that sleeps with the mouth open; and with mankind I believe the habit, which is not natural, is generally confined to civilized communities, where he is nurtured and raised amidst enervating luxuries and unnatural warmth where the habit is easily contracted, but carried and practiced with great danger to life in different latitudes and different climates; and in sudden changes of temperature, even in his own house.”
To Catlin, the breathing habits of the Western world were inherently unhealthy. His book Shut Your Mouth and Save Your Life claimed that the secret to longevity rested in breathing through the nose as well as a healthy dose of temperature variation. Catlin encouraged people to train themselves to sleep with their mouths closed, arguing that the nose is a natural filter of pathogens.
While much of Catlin’s logic remained mired in the scientific understandings of the 19th century, Mackenzie and others like Patrick McKeown, author of The Oxygen Advantage, have reincarnated the philosophy for the modern world. The nose is nature’s most effective air decontaminator, and it also conditions our bodies to handle stress. Mouth breathing—of which I have an almost-40-year-long habit—is for emergency situations where the power boost that comes from a rapid gas exchange is more important than the nose’s filtering properties.
To put it another way, breathing through the nose creates parasympathetic tone, while mouth breathing activates the sympathetic nervous system. Mackenzie starts to tell me about how the nose naturally humidifies and conditions incoming air to a steady 96 degrees before it hits the lungs, and how the sinuses will release nitrogen-oxide—a vasodilator—during nasal breathing. As I dutifully take notes on the miracle of nasal breathing, he gets more animated and pulls up a list of citations that correlate respiration rates with different diseases.
Where healthy people move six to seven liters of air through their lungs in a given minute, diseases seem to increase respiration rates. He starts reading down a list of medical citations. “Diabetes 15 breaths per minute, asthma fourteen, heart disease 12, cystic fibrosis 18, liver cirrhosis 18...” He trails off and just forwards me the studies over email. I imagine a hospital full of enfeebled mouth breathers, drowning in air. While the studies check out, it’s important to note that just because disease pathology correlates with higher respiration rates, it doesn’t mean that higher respiration causes the illnesses. What we can infer, however, is that sick people breathe more, which likely means that people who are sick don’t breathe as efficiently as those who are well. It’s not too far of a stretch to think that good breathing hygiene might also help keep someone healthy. By expressing choice in how you breathe, you have the power to wedge in control over your overall well-being. With training, the conscious programming eventually forms a habit that turns nasal breathing to autonomic control, and you’ve hacked your health.
Beyond the disease correlations, for Mackenzie, nasal breathing is also one of the easiest ways to build up CO₂ tolerance. While mouth breathers exchange air easily, they also habitually blow off more CO₂ than they should. Over time the passive hyperventilation becomes the norm, and it’s harder to go back to a nasal baseline. This is why many people find it difficult to start nasal breathing once they reach adulthood.
I ask him to show me his program, and he suggests we try a little experiment on a stationary bike. He straps me into a heart monitor and ask me to warm up on something called a Concept 2 stationary bike.
The goal of the new training program is to keep a parasympathetic tone during a heavy workload—but first, as always, we need a baseline reading. The ultimate goal will be to train the resting metabolism for high performance. Mackenzie’s hypothesis is that breathing through the nose during training periods will allow for higher performance when you switch over to sympathetic workouts at higher intensities.
He shakes his head when he sees how my feet make contact with the pedals. I have walked with my feet tilted outwards like a duck for my entire life, which translates into being a pretty terrible runner. This is why I’ve always preferred bikes. “Straighten out your feet and each stroke will give you more power,” he says. When I ask how someone is supposed to correct a lifetime of bad habits, he shrugs and says, “It’s just a mental thing. Your brain gives the new instructions, and eventually your body will follow.” Here, the repeated activity is a wedge that trains the nervous system to transform the gait over time into something that I don’t have to spend any mental energy on: using conscious effort to lock in changes so that they become unconscious. So I tweak my legs back into the alignment he asks for. True to form, pushing the pedals has more power. The wattage on the bike jumps upward. He flashes an “I told you so” smile. I was losing torque with my ordinary gait. In a way, correcting breathing patterns will rely on the same sort of willpower. My ordinary gait is a habit, but it’s a habit that I can (theoretically) correct with a little conscious intervention. The same goes for breathing.
I warm up on the bike until my heart rate peaks at 170 beats per minute (BPM), and then he tells me that he wants to see how long it takes me to recover. I’m supposed to try to bring it down to below 100. At first I sit on the bike and breathe slowly, but my heart barely budges. I migrate to the rubber mat on the floor. It takes a full seven minutes before I get to 100. Mackenzie says that ideally, a person should be able to recover to a resting BPM of 100 in under two minutes.
We take a rest and come back to the bike about an hour later. This time, he says, he’s going to put me through a staged intensity test, where I’ll just use my nose to breathe. We start at a meandering pace of 120 watts per minute, and every minute, I’m supposed to increase my physical output by 10 watts. The test will end the second that I start to switch from nasal breathing to mouth breathing. That switch is the inflection point at which parasympathetic tone ends and the sympathetic system takes over. He figures I’ll make it 10 stages.
After eight minutes, the slow movement of my nasal breathing gets deeper and faster, and I focus on a single point just above the wattage monitor—trying to sink deeper into my sensations and widening my peripheral vision, which Huberman told me activates parasympathetic responses.
“You’re doing much better than I expected,” Mackenzie comments as I push the pedals. I wonder if that’s an invitation to stop, but I don’t feel near done yet. Two stages later, I’m still going strong. Then my nose starts to run. A long, clear dribble threatens to escape. I wipe at it, not wanting to open my lips and give in before I’m done. Two more stages and the pattern of air out of my nose is more ragged. My heart rate is closing in on 170. He tells me to dismount and recover again.
I’m down to 100 BPM in six minutes. It’s a modest improvement, but something that he’s sure I can train.
“One of the differences between a good athlete and a great one is how quickly they recover,” says Mackenzie. “And our hypothesis is that we can train recovery.” It’s a game-changing notion. If you can tweak how the body deals with stress after exertion, then even resting becomes an active part of an athletic training program.
Mackenzie’s own workouts are an order of magnitude more intense than what he’s having me do on this stationary bike, and he’s been a lifelong athlete and endurance runner who is no stranger to suffering. But after switching to nasal breathing, he says, his recoveries are so much easier. “I just don’t feel sore anymore.”
Mouth breathing during intense workouts allows a person to blow off CO₂ too quickly. This helps buffer the intensity of the pain of exertion and artificially lowers blood acidity. Nasal breathing does the opposite: Acid levels rise sharply during the workout compared to hyperventilation. It’s a little counterintuitive. Part of me thinks that more acid in the workout means more acid in recovery, and thus more soreness afterward. But that isn’t what happens. According to Mackenzie, soreness occurs because the body has to restock the lost CO₂ that it blew off during the workout so that during recovery, acid levels actually go higher. It’s sort of like a hangover after the euphoria of being drunk: Every chemical high gets balanced out with a chemical low over time. The high-intensity exertion pushes the body into a sympathetic state, and since you can’t blow it off quickly, CO₂ builds up in the system. The body has to develop a tolerance to the acid, and during recovery, you don’t have to compensate and restock levels as much.
Tomorrow, after I’m rested, he plans to test me again—this time with just mouth breathing. The idea is that I’ll be able to complete more stages and maintain a higher heart rate. And a higher heart rate is the marker for what a recovery will feel like.
…
That evening, I’m sitting at the long wooden dinner table in his living room. We nosh on plantains and enchiladas that his wife picked up from somewhere across the Bay. I’ve learned a lot, but I’m still curious about how an elite training program can benefit the average Joe. After all, not everyone needs to be a super-athlete. How does his breathwork translate into an everyday wedge to make us more resilient?
I ask him why ordinary people would want to go through all these new breathing protocols if their lives are going along fine as is. He nods. “I’m not doing this just to make someone’s gym workouts that much more hard-core. It’s about being a person with a body. I want to find that razor edge in all things, where you aren’t so agitated that you make mistakes, but aren’t so relaxed that you don’t notice the environment around you. At the end of the day, the Wedge is about balance. And once you discover that mental state where you’re connected but objective at the same time, you have an edge in all aspects of life,” he says.
The next day, it doesn’t go exactly the way of his earlier hypothesis. I go through another 12 rounds of exercise with only breathing through my mouth. Perhaps it’s because I already have a high CO₂ tolerance from practicing extended breath holds for the past few years, but the results surprise him. In both tests, my heartbeat spikes to high levels almost immediately—proving once again that I’m no super-athlete. Well-tuned athletes’ heart rates move upward smoothly, without sudden spikes. Strangely, my heart rate was higher when only breathing through the nose by three beats per minute. This is the opposite of his usual predictions, but perhaps, he says, it’s because I’m already so good with CO₂. Whatever the case, he urges me to keep nose breathing when I do longer bike rides back home in Colorado. It will be a slower process, but he predicts that I’ll raise the floor. Time will prove him right.
And that notion of floors and ceilings leads me to another question about human baselines for stress in general. Breathing is a powerful wedge to alter internal states, but there are floors and ceilings to every type of stress level. It stands to reason that a chaotic environment triggers chaotic bodily reactions while subdued ones lead to relaxation. After all, we are the environment that we inhabit. So when we alter the outside world, it’s really a wedge into our internal state. And the changes don’t only affect the present. Our brain lives in perpetual past, so as we create more neural symbols, those past environments continue to affect how we feel and respond in the future. The choices about our environment that we make in the moment both defines who we are as individuals and how we connect to the universe at large.
So far, I’ve learned important ways that my relationship with the environment alters my internal state. In Huberman’s lab, I learned that human consciousness is a recursive process: Every sensation I feel bonds with my emotional state to create a library of neural symbols that my lizard brain uses to make sense of the world at large. I’ve found how I can use this underlying mechanism to transform fear into joy and see the world from the perspective of flow. Next I delved deep into a breathing pattern that shut down my higher mental functions and, inexplicably, felt connected to something greater than myself. With Mackenzie, I’ve learned how my automatic breathing patterns can trigger anxiety or contentedness and that I might be able to train anxiety away through breathwork alone. All this new information has helped me gain a deeper understanding of how the Wedge operates at the synaptic and physiological levels. Decisions about mindset alter our symbolic neurology, while breathwork changes the sensory pathways that the body uses to make decisions about the outside world.
Now I want to think about all of this from the perspective of the sequential lineup of Russian dolls. If all I am is the sum of internal and external influences, then what happens to my sense of self when I remove my body from as many external inputs as possible? How does the superorganism affect the body when it’s cut off from the outside world? This time, I don’t have to go back to California to answer a big question.
Instead, I’m headed to Oklahoma to isolate my brain.