By the late 1950s, Buteyko left the hospitals of Moscow and headed to Akademgorodok (“Academic City”), a cluster of 35 concrete-block research facilities located in central Siberia. The distant location was by design. For the past few years, the Soviet government had sent tens of thousands of the finest space engineers, chemists, physicists, and others to live in secrecy among the laboratories. Their job was to develop cutting-edge technologies aimed at ensuring the Soviet Union’s dominance. In many ways it was a Soviet Silicon Valley, but without the fleece vests, kombucha, sunshine, Teslas, and civil liberties.

Buteyko had moved there at the request of the USSR Academy of Medical Sciences, the Soviet equivalent to the Centers for Disease Control and Prevention. After his epiphany in the asthma ward, he’d pored over research papers and analyzed hundreds of patients. He’d become convinced that breathing too much was the culprit behind several chronic diseases. Like Bohr and Henderson, Buteyko was fascinated with carbon dioxide, and he too believed that increasing this gas by breathing less could not only keep us fit and healthy. It could heal us as well.

At Akademgorodok he set out to conduct the most exhaustive breathing experiments that science had ever attempted. He collected a staff of more than 200 researchers and assistants in a sweeping city hospital called the Laboratory of Functional Diagnostics. Subjects would come in and lie on a gurney, sandwiched between stacks of machines. Phlebotomists would plug catheters into their veins while other researchers stuck hoses into their throats and electrodes around the heart and head. As the subjects breathed in and out, a primitive computer recorded 100,000 bits of data per hour.

The sick and healthy, young and old—more than a thousand of them came to Buteyko’s lab. The patients with asthma, hypertension, and other ailments consistently breathed the same: too much. They often inhaled and exhaled through the mouth, packing in 15 liters or more of air per minute. Some breathed so loudly they could be heard several feet away. The readouts showed that they had plenty of oxygen in their blood, but much less carbon dioxide, about 4 percent. Resting heart rates were up to 90 beats per minute.

The healthiest patients breathed alike, too: less. They’d inhale and exhale about ten times a minute, taking in a total of about five to six liters of air. Their resting pulses ranged from around 48 to 55, and they had 6.5 to 7.5 percent carbon dioxide levels in their exhaled breath.

Buteyko developed a protocol based on the breathing habits of these healthiest patients, which he’d later call Voluntary Elimination of Deep Breathing. The techniques were many and they varied, but the purpose of each was to train patients to always breathe as closely as possible to their metabolic needs, which almost always meant taking in less air. How many breaths we took per minute was less important to Buteyko, as long as we were breathing no more than about six liters per minute at rest.

Within a few sessions of practicing these techniques, patients reported tingling and heat in their hands and toes. Their heart rates would slow and stabilize. The hypertension and migraines that had debilitated so many of them would begin to disappear. Those already in good health felt even better. Athletes claimed big gains in performance.

Around this time, a few thousand miles east, in the industrial factory town of Zlín, Czechoslovakia, a gangly, five-foot-eight-inch runner named Emil Zátopek was experimenting with his own breath-restriction techniques.

Zátopek never wanted to become a runner. When the management at the shoe factory where he was working elected him for a local race, he tried to refuse. Zátopek told them he was unfit, that he had no interest, that he’d never run in a competition. But he competed anyway and came in second out of 100 contestants. Zátopek saw a brighter future for himself in running, and began to take the sport more seriously. Four years later he broke the Czech national records for the 2,000, 3,000, and 5,000 meters.

Zátopek developed his own training methods to give himself an edge. He’d run as fast as he could holding his breath, take a few huffs and puffs and then do it all again. It was an extreme version of Buteyko’s methods, but Zátopek didn’t call it Voluntary Elimination of Deep Breathing. Nobody did. It would become known as hypoventilation training. Hypo, which comes from the Greek for “under” (as in hypodermic needle), is the opposite of hyper, meaning “over.” The concept of hypoventilation training was to breathe less.

Over the years, Zátopek’s approach was widely derided and mocked, but he ignored the critics. At the 1952 Olympics, he won gold in the 5,000 and 10,000 meters. On the heels of his success, he decided to compete in the marathon, an event he had neither trained for nor run in his life. He won gold. Zátopek would claim 18 world records, four Olympic golds and a silver over his career. He would later be named the “Greatest Runner of All Time” by Runner’s World magazine. “He does everything wrong but win,” said Larry Snyder, a track coach at Ohio State at the time.

Hypoventilation training didn’t exactly take off after Zátopek. His anguished face, teeth grinding and eyes wincing like a Matthias Grünewald Jesus, became his trademark look as he crossed the finish line, often in first place. It all seemed miserable, because it was, and most athletes steered clear.

Then, decades later, in the 1970s, a hard-assed U.S. swim coach named James Counsilman rediscovered it. Counsilman was notorious for his “hurt, pain, and agony”–based training techniques, and hypoventilation fit right in.

Competitive swimmers usually take two or three strokes before they flip their heads to the side and inhale. Counsilman trained his team to hold their breath for as many as nine strokes. He believed that, over time, the swimmers would utilize oxygen more efficiently and swim faster. In a sense, it was Buteyko’s Voluntary Elimination of Deep Breathing and Zátopek hypoventilation—underwater. Counsilman used it to train the U.S. Men’s Swimming team for the Montreal Olympics. They won 13 gold medals, 14 silver, and 7 bronze, and they set world records in 11 events. It was the greatest performance by a U.S. Olympic swim team in history.

Hypoventilation training fell back into obscurity after several studies in the 1980s and 1990s argued that it had little to no impact on performance and endurance. Whatever these athletes were gaining, the researchers reported, must have been based on a strong placebo effect.

In the early 2000s, Dr. Xavier Woorons, a French physiologist at Paris 13 University, found a flaw in these studies. The scientists critical of the technique had measured it all wrong. They’d been looking at athletes holding their breath with full lungs, and all that extra air in the lungs made it difficult for the athletes to enter into a deep state of hypoventilation.

Woorons repeated the tests, but this time subjects practiced the half-full technique, which is how Buteyko trained his patients, and likely how Counsilman trained his swimmers. Breathing less offered huge benefits. If athletes kept at it for several weeks, their muscles adapted to tolerate more lactate accumulation, which allowed their bodies to pull more energy during states of heavy anaerobic stress, and, as a result, train harder and longer. Other reports showed hypoventilation training provided a boost in red blood cells, allowing athletes to carry more oxygen and produce more energy with each breath. Breathing way less delivered the benefits of high-altitude training at 6,500 feet, but it could be used at sea level, or anywhere.

Over the years, this style of breath restriction has been given many names—hypoventilation, hypoxic training, Buteyko technique, and the pointlessly technical “normobaric hypoxia training.” The outcomes were the same: a profound boost in performance.* Not just for elite athletes, but for everyone.

Just a few weeks of the training significantly increased endurance, reduced more “trunk fat,” improved cardiovascular function, and boosted muscle mass compared to normal-breathing exercise. This list goes on.

The takeaway is that hypoventilation works. It helps train the body to do more with less. But that doesn’t mean it’s pleasant.

Olsson and I emerge from the shady tranquility of Golden Gate Park, stopping to face the wind-ripped Pacific Ocean. We’ve just jogged a few miles, inhaling fast and exhaling very long breaths to a count of about seven or higher, trying to keep our lungs roughly half full. I want to believe that this training may be helping me as it helped Zátopek, Counsilman’s swimmers, Wooron’s runners, and everyone else, but the past several minutes have been a challenge. A half hour into all this I’m beginning to resent my life choices. I can’t figure out if it’s bad luck or shortsightedness that has led me to repeatedly pursue topics of research like freediving, Voluntary Elimination of Deep Breathing, and hypoventilation therapy that require me to hold my breath and torture my lungs for hours a day.

“The key is to find a rhythm that works for you,” Olsson keeps saying. The rhythm is definitely not working. I return to my more manageable practice, inhaling for two steps and exhaling for five, a pattern competitive cyclists use. This isn’t exactly comfortable, but it’s tolerable.

We run across the cracked asphalt of a beachside parking lot, passing a few rusting Winnebagos and hopping over condom wrappers and smashed cans of malt liquor before heading back across the highway. Minutes later we’re back in the quietude of the park, treading a dirt path beneath an understory of trees along a black pond filled with quacking ducks.

That’s when it starts to hit me: an intense heat at the back of my neck and pixelated vision. I’m still jogging, exhaling long breaths, but it feels as though I’m simultaneously jumping headfirst into warm, thick liquid. I run a little harder, breathe a little less, and feel heat, heavy like hot syrup, seeping down into my fingertips, toes, arms, and legs. It feels great. The warmth moves higher through my face and wraps around the crown of my head.

This must be the good headache Olsson was talking about, of carbon dioxide increasing and oxygen dislodging from hemoglobin to those hungry cells, of the vessels in my brain and body expanding, so engorged with fresh blood that they’re sending dull pain signals to my nervous system.

Just when it feels like I’m about to reach some kind of existential crescendo, the little foot trail widens. The bored buffalo appear, rustling behind a chain-link fence. A dozen yards away is the lot of the Golden Gate Angling and Casting Club. My car is beside it, and we’re done.

There are no huge life epiphanies as we drive home. I can’t say I’m feeling euphoric, but that’s OK. My little jog proved there’s much to gain from this less approach. At the same time, such extreme training would be useful only for those willing to endure hours of red-faced, sweaty suffering.

Healthy breathing shouldn’t be so much work. Buteyko knew this, and he rarely, if ever, prescribed such brutal methods to his patients. After all, he wasn’t interested in coaching elite athletes to win gold medals. He wanted to save lives. He wanted to teach techniques of breathing less that could be practiced by everyone, regardless of their state of health, age, or level of fitness.

Over his career, Buteyko would be censured by medical critics; he’d be physically attacked and, at one point, have his laboratory torn up. But he pressed on. By the 1980s, he had published more than 50 scientific papers and the Soviet Ministry of Health had recognized his techniques as effective. Some 200,000 people in Russia alone had learned his methods. According to several sources, Buteyko was once invited to England to meet with Prince Charles, who was suffering from breathing difficulties brought on by allergies. Buteyko helped the prince, and he helped heal upward of 80 percent of his patients suffering from hypertension, arthritis, and other ailments.

Voluntary Elimination of Deep Breathing was especially effective in treating respiratory diseases. It seemed to work like a miracle for asthma.

In the decades since Buteyko first started training patients to breathe less, asthma has become a global epidemic. Nearly 25 million Americans now suffer from it—that’s about 8 percent of the population, and a fourfold increase since 1980. Asthma is the leading cause of emergency room visits, hospitalizations, and missed school days for children. It is considered a controllable but incurable disease.

Asthma is an immune system sensitivity that provokes constriction and spasms in the airways. Pollutants, dust, viral infections, cold air, and more can all lead to attacks. But asthma can be brought on by overbreathing, which is why it’s so common during physical exertion, a condition called exercise-induced asthma that affects around 15 percent of the population and up to 40 percent of athletes. At rest or during exercise, asthmatics as a whole tend to breathe more—sometimes much more—than those without asthma. Once an attack starts, things go from bad to worse. Air gets trapped in the lungs and passageways constrict, which makes it harder to push air out and back in. More breathing but more feelings of breathlessness ensue, more constriction, more panic, and more stress.

The worldwide annual market for asthma therapies is $20 billion, and drugs often work so well that they can feel like a virtual cure. But drugs, in particular oral steroids, can have horrendous side effects after several years, including deteriorating lung function, worsened asthma symptoms, blindness, and increased risk of death. Millions of asthma sufferers already know this, and are experiencing these problems for themselves. Many of them have trained themselves to breathe less and reported dramatic improvement.

For several months before the Stanford experiment, I interviewed Buteyko practitioners and collected their stories.

One was David Wiebe, a 58-year-old luthier of cellos and violins from Woodstock, New York, whom I’d read about in The New York Times. Wiebe had suffered from severe asthma since he was ten. He used bronchodilators up to 20 times a day, along with steroids, in an effort to keep his symptoms at bay. His body became tolerant of drugs, which meant that Wiebe had to increase the dose. After decades of constant use, the steroids weakened his eyesight, a condition called macular degeneration. If he kept taking them, Wiebe would go blind; if he stopped taking them, he wouldn’t be able to breathe and might die of an asthma attack.

Within three months of learning how to breathe less, Wiebe was using no more than one inhaler puff a day, and he’d cut out steroids entirely. He claimed to feel few asthma symptoms at all. For the first time in five decades he could breathe easy. Even Wiebe’s pulmonologist was impressed, confirming that there was a marked improvement in Wiebe’s asthma and overall health.

There were others. Like the chief information officer at the University of Illinois at Urbana-Champaign, who had also suffered from debilitating asthma his whole adult life, and who, like Wiebe, reported few symptoms of asthma within weeks of retraining himself to breathe less. “I’m a new man,” he wrote. There was the 70-year-old woman I’d spent an hour with at a Whole Foods café, who had experienced crippling asthma the past six decades and could hardly walk a few blocks without having an attack. After a few months of breathing less she was hiking for hours a day and on her way to travel in Mexico. “This is nothing short of a miracle,” she told me. There was the mom from Kentucky who endured such horrendous breathing problems that she contemplated suicide. There were also athletes like Olympians Ramon Andersson, Matthew Dunn, and Sanya Richards-Ross, who had used breathing less methods. All of them claimed to have gained a boost in performance and blunted the symptoms of respiratory problems, simply by decreasing the volume of air in their lungs and increasing the carbon dioxide in their bodies.

The most convincing scientific validation of breathing less for asthma came by way of Dr. Alicia Meuret, director of the Anxiety and Depression Research Center at Southern Methodist University in Dallas. In 2014, Meuret and a team of researchers gathered 120 randomly selected asthma sufferers, measured their pulmonary lung functions, lung size, and blood gases, and then gave them a handheld capnometer, which tracked the carbon dioxide in their exhaled breath.

Over four weeks, the asthmatics would carry the device around and practice breathing less to keep their carbon dioxide levels at a healthy level of 5.5 percent. If the levels dipped, the patients would breathe less until the carbon dioxide levels rose back. A month later, 80 percent of the asthmatics had raised their resting carbon dioxide level and experienced significantly fewer asthma attacks, better lung function, and a widening of their airways. They all breathed better. The symptoms of their asthma were either gone or markedly decreased.

“When people hyperventilate, there is something very strange happening,” Meuret wrote. “In essence they are taking in too much air. But the sensation that they get is shortness of breath, choking, air hunger, as if they’re not getting enough air. It’s almost like a biological system error.” Willing the body to breathe less air appeared to correct that system error.

By the end of his career, and the end of his life in 2003 at the age of 80, Buteyko would become a bit of a mystic. He barely slept and claimed that his techniques could not only heal illnesses but promote intuition and other forms of extrasensory perception. He was convinced that heart disease, hemorrhoids, gout, cancer, and more than 100 other diseases were all caused by carbon dioxide deficiency brought on by overbreathing. He even considered asthma attacks less a problem, less a “system malfunction,” and more a compensatory action. That airway constriction, wheezing, and shortness of breath was the body’s natural reflex to breathe less and more slowly.

For these reasons and others, Buteyko and his methods have been largely dismissed by today’s medical community as pseudoscience. Nonetheless, a few dozen researchers over the past few decades have attempted to gain some kind of real scientific validation on the restorative effects of breathing less. One study at the Mater Hospital in Brisbane, Australia, found that when asthmatic adults followed Buteyko’s methods and decreased their air intake by a third, symptoms of breathlessness reduced by 70 percent and the need for reliever medication decreased by around 90 percent. A half-dozen other clinical trials showed similar results. Meanwhile, the Papworth Method, a breathing-less technique developed in an English hospital in the 1960s, was also shown to cut asthma symptoms by a third.*

Still, nobody seems to know exactly why breathing less has been so effective in treating asthma and other respiratory conditions. Nobody knows exactly how it works. There are several theories.

“It is a deficiency in the body that causes symptoms,” said Dr. Ira Packman, an internist and former medical expert for the Pennsylvania Insurance Department who overcame his own debilitating asthma by breathing less. “Replace the deficient element,” he told me, “and the patient gets better.”

Packman explained that overbreathing can have other, deeper effects on the body beyond just lung function and constricted airways. When we breathe too much, we expel too much carbon dioxide, and our blood pH rises to become more alkaline; when we breathe slower and hold in more carbon dioxide, pH lowers and blood becomes more acidic. Almost all cellular functions in the body take place at a blood pH of 7.4, our sweet spot between alkaline and acid.

When we stray from that, the body will do whatever it can to get us back there. The kidneys, for instance, will respond to overbreathing by “buffering,”* a process in which an alkaline compound called bicarbonate is released into the urine. With less bicarbonate in the blood, the pH lowers back to normal, even if we continue to huff and puff. It’s as if nothing ever happened.

The problem with buffering is that it’s meant as a temporary fix, not a permanent solution. Weeks, months, or years of overbreathing, and this constant kidney (renal) buffering will deplete the body of essential minerals. This occurs because as bicarbonate leaves the body, it takes magnesium, phosphorus, potassium, and more with it. Without healthy stores of these minerals, nothing works right: nerves malfunction, smooth muscles spasm, and cells can’t efficiently create energy. Breathing becomes even more difficult. This is one reason why asthmatics and other people with chronic respiratory problems are prescribed supplements like magnesium to stave off further attacks.

Constant buffering also weakens the bones, which try to compensate by dissolving their mineral stores back into the bloodstream. (Yes, it’s possible to overbreathe yourself into osteoporosis and increased risk of bone fractures.) This unending grind of imbalances and compensations, of deficiencies and strain, will eventually break the body down.

Packman was quick to point out that not all respiratory illness sufferers and other sick people have a carbon dioxide deficiency problem. Those with emphysema, for instance, may have dangerously high levels of carbon dioxide because they’ve got too much stale air trapped inside. Others may test with completely normal blood gas and pH levels. But such nitpicking, he said, missed the larger point.

All these people have a breathing problem. They’re stressed, they’re inflamed, they’re congested, and they struggle to get air in and out of their lungs. And it’s these breathing problems that slow, paced, less techniques are so effective at fixing.

Over several months leading up to the Stanford experiment, I visited with several Buteyko teachers and other low-breathing devotees. They told me the same story, of how they’d been plagued by some chronic respiratory illness that no drug or surgery or medical therapy could fix. Of how they all “cured” themselves with nothing more than breathing less. The techniques they used varied, but all circled around the same premise: to extend the length of time between inhalations and exhalations. The less one breathes, the more one absorbs the warming touch of respiratory efficiency—and the further a body can go.

This shouldn’t come as much of a surprise. Nature functions in orders of magnitude. Mammals with the lowest resting heart rates live the longest. And it’s no coincidence that these are consistently the same mammals that breathe the slowest. The only way to retain a slow resting heart rate is with slow breaths. This is as true for baboons and bison as it is for blue whales and us.

“The yogi’s life is not measured by the number of his days, but the number of his breaths,” wrote B. K. S. Iyengar, an Indian yoga teacher who had spent years in bed as a sickly child until he learned yoga and breathed himself back to health. He died in 2014, at age 95.

I’d hear this repeated over and over again by Olsson during our early Skype chats and again throughout the Stanford experiment. I’d read about it in Stough’s research. Buteyko and the Catholics, Buddhists, Hindus, and 9/11 survivors were aware of it as well. By various means, in various ways, in various eras of human history, all these pulmonauts discovered the same thing. They discovered that the optimum amount of air we should take in at rest per minute is 5.5 liters. The optimum breathing rate is about 5.5 breaths per minute. That’s 5.5-second inhales and 5.5-second exhales. This is the perfect breath.

Asthmatics, emphysemics, Olympians, and almost anyone, anywhere, can benefit from breathing this way for even a few minutes a day, much longer if possible: to inhale and exhale in a way that feeds our bodies just the right amount of air, at just the right time, to perform at peak capacity.

To just keep breathing, less.