Deep, Slow Breathing: An Antidote to Our Age of Anxiety?

This article appeared in the September/October 2021 issue of Discover magazine as "Know Your Breath." Become a subscriber for unlimited access to our archive.

Some of us are better at holding our breath than others. But we’ve all been put to the test.

Tune in to your body next time you plunge your head into water. Close your lips and conserve the air within. Many people describe a wave of relaxation in this moment — an all-consuming calm, a quieting of the mind, a slowed mental state — until the lungs demand another breath. When that happens, most of us experience a rush of anxiety. The mind goes on immediate alert at the mere prospect of lacking oxygen, even if your blood and organs have plenty for another minute or two. But you don’t need to go swimming to find this anxiety.

You’ve likely held your breath plenty over the past tumultuous year and a half. Treading cautiously in supermarket aisles. White-knuckling it through social isolation, then reentry. Gasping at political upheaval and racial tensions. On many levels, 2020 forced humans everywhere to consider their breath as an act of survival.

For most of us, thinking about — let alone improving — our respiratory system has always been more reactionary than preventative. Things must veer woefully off course before we pay attention. Even within the medical field, lung specialists such as pulmonologists mostly study how to treat ailments like asthma, emphysema or respiratory illness. Only recently have researchers begun to truly examine the fine-tuned ways we breathe on a daily basis. Their work suggests we could all be doing much better. Specifically, conscious breath work can be a powerful tool and effective medicine for the body and mind.

Many humans have grown up to be chronic shallow breathers. To illustrate, take a few seconds now and notice your own natural breathing pattern. At the end of your natural exhale, when your body is ready to inhale again, don’t. Instead, exhale more air; then even more, forcing it out of your mouth. If you found plenty still to exhale, it’s mostly coming from the lungs, specifically the bottom half that gets stimulated by the diaphragm muscle near your belly.

Like an overzealous server at a restaurant, adults are prone to refill their lungs while they’re half full (or, more aptly, half empty, in this scarcity mindset). Shallow breathing avoids engaging the diaphragm near your belly, and it’s excessive by definition.

“As we age, we put on weight, take on stress and stop breathing with our diaphragm,” says Michael J. Stephen, a pulmonologist at Thomas Jefferson University. “This is ineffective breathing.”

If you pushed through to achieve that full exhale a moment ago, you might have noticed a prolonged, satisfying inhale immediately followed. Do it on repeat for a simple practice of deeper, slower breathing. In your body, this biologically signals “all is well” to the brain and a full cast of players. The heart rate slows; the vagus nerve engages, which is a vital component in the rest-and-restore parasympathetic nervous system; and the brain releases your feel-good serotonin and dopamine hormones. All you have to do is think about your breath and treat it like a conductor’s baton. Or, in Stephen’s words: “It’s a natural Prozac.”

Stephen published his first book, Breath Taking, last year. It was one of at least two new books in 2020 that renewed broad interest in the nuance and science of breathing — along with journalist James Nestor’s New York Times bestseller Breath. Both works, along with a wave of recent studies, demonstrate how slow, deep breathing can stimulate much more than the lungs. Various research has connected conscious breath work to treating symptoms of anxiety, sleep apnea, PTSD, chronic pain and depression. The mysterious ways that breath influences blood pressure and inflammation could even usher in wide-reaching treatments for heart disease, the No. 1 killer for humans worldwide.

Compared to dieting or fitness, breathing has been a sort of elephant in the room of health and wellness in recent history. And yet, every human is vastly more dependent on their breath than nearly any other function, from a sheer nutrient standpoint. Oxygen is a fundamental building block for all the metabolizing, muscle-building, fat burning and resting that has captured the attention of the wellness world.

Consider that each time you take air into the nose and mouth and force it down to the lungs, you’re distributing oxygen through the bloodstream to every finger and toe, to the nervous system and the brain. Then, of course, you exhale. Most of us mindlessly repeat this cycle some 20,000 times a day, exchanging more than 2,600 gallons of air. These figures are based on a widely accepted normal respiratory rate of 12 to 16 breaths per minute in resting adults — or even up to 20 breaths per minute, according to some medical literature.

Donald Noble, a physiologist and behavioral scientist at Emory University, wonders if humans have normalized an excessive respiratory rate. “There may be good reasons to aim lower,” he says. His work has investigated a biological vibration coinciding with a respiratory rate of six breaths per minute, about half of the so-called norm.

Noble’s research explores how breath informs and interacts with the cardiovascular system, neuropathways and relay neurons and receptors within them. All these elements have a close connection. And many seem to function best when synchronized, according to a review paper Noble published in late 2019 in Frontiers in Physiology.

Read More: Holotropic Breathing Promises Psychedelic-Like Trips Without the Drugs. Is It Safe?

As humans slow their respiratory rate to about six breaths per minute, that frequency translates to about 0.1 Hertz. Incidentally, similar breath rates have been recorded in numerous studies over the years that observed how breathing can synchronize . with the heart rate while people practice yoga mantras, Zen meditation and even rosary prayers.

Noble’s work has shown how tiny mechanisms throughout our cardiovascular system oscillate at that same frequency of 0.1 Hertz.

“It’s almost like an inherent rhythm,” he says. “Your breath may be reinforcing this rhythm that you already have going on in the background.”

Specifically, he’s talking about the resonance of Mayer waves, which may help regulate blood pressure in our arteries.

These waves seem to oscillate around 0.1 Hertz. When we inhale and exhale at that rate, our respiration has the potential to optimize the rhythm of various mechanisms and align them with our heart rate. “When you breathe at that same rate, it’s like pushing the swing at the perfect moment,” Noble says.

These findings land alongside numerous studies that demonstrate a connection between mindful, deep breathing at various rates and improved blood pressure. Because our blood vessels extend virtually everywhere in the body, the potential benefits of this vascular synchronization are vast, including increased metabolic efficiency and reduced oxygen consumption. Ultimately, these foundational systems inform daily wellness, whether you’re just battling the plight of aging or competing in triathlons. “Together, they presumably improve physiology,” Noble says.

Earlier in 2020, a group of researchers published similar findings in Clinical Neurophysiology, drawing a potential link between six breaths per minute, or 0.1 Hertz, and heart rate variability (HRV) in humans. This health metric measures the variation of time between each heartbeat; low HRV has been linked to worsening depression and anxiety. Tech companies now sell devices to track your HRV in real time. A separate study in 2018 demonstrated how ultra-slow breathing — at 0.05 Hertz, or three breaths per minute — might induce altered states of awareness, based on sleep-like brain waves seen in people while meditating.

As the data stacks up, Noble and other researchers emphasize that there’s likely no magical perfect rate. It seems to vary from person to person. More importantly, their work can show how specific breath rhythms are ideal for unique circumstances and needs. Sprinting, for example, or having sex might demand very different respiratory patterns than, say, swimming. Especially if you swim like Claire Paris.

Paris is a master at holding her breath. Based in Miami, the French-American scientist regularly practices six-minute-plus breath holds in a pool, and dives more than 200 feet down in the ocean on a single gulp of air. She’s one of those people who feels an exceptional calm and stillness when immersed in water.

“Underwater was always my sanctuary,” Paris says.

She grew up on the Atlantic coast of France and spent part of her teen years in a fishing village in West Africa, where she’d join fishers at sunrise in their wooden boats. Later, she obtained a Ph.D. in oceanography. The ocean and swimming, she says, have felt like home since she was young. But it wasn’t until her 50th birthday in 2008 that she formally learned the mechanics of freediving. This practice trains the lungs and body to withstand significant apnea (breath holding) and depth underwater, without scuba equipment.

Paris got certified, then discovered new potential for these skills while conducting research in Belize with a National Science Foundation grant. She was releasing fish larva in a drifting chamber to study how they navigate their way to a reef ecosystem. Along the way, many died while sloshing around in the container on the choppy surface. Paris and a research partner then started diving down about 30 feet to effectively release the fish underwater.

Today, her freediving practice is equal parts competitive, self-care and practical. Every six months, she travels to Dean’s Blue Hole in the Bahamas to service a hydrophone located on a limestone ledge roughly 50 feet underwater. For nearly a decade, the equipment has been recording sounds above the world’s second deepest marine sinkhole (second to Dragon Hole in the South China Sea). Freediving helped solve some costly and logistical hurdles accessing the microphone submerged off a remote island, where storing scuba tanks and coordinating dives pose challenges.

Similarly, Paris explains how freediving can be a vital scientific tool in under-resourced parts of the world, low-budget research scenarios or environments where bubbles from scuba equipment would scare off marine life. Also, some protected refuges prohibit dive equipment. She points out that many cultures around the world have tapped into extraordinary breath-holding abilities for centuries, often to secure food in island communities or even sabotage sea vessels in conflicts. Modern dive equipment largely has displaced this human skill. But at the start of 2020, Paris launched a first-of-its-kind scientific freediving course at the University of Miami. The class is designed to support marine researchers in the field.

Beyond her ocean studies, she also competes in international freediving events. In May, she claimed her fifth U.S. women’s record in freediving. One of those involved swimming 603 feet underwater in a pool — the span of an American football field and back, plus a few feet into the end zone — with no supportive oxygen. One of her competition strategies is to avoid wearing goggles. “I like the sensation of the water running on my eyes,” Paris says. “You have a lot of receptors on your face that trigger the dive reflex.”

This reflex, also known as the mammalian dive reflex, can sound like a mix of woo-woo mysticism and mutant superpowers. But it’s actually documented in scientific literature. Essentially, submersion in water triggers a series of rapid physiological shifts in humans and other warm-blooded animals. Many of these mechanisms directly preserve oxygen by reducing blood flow to nonessential extremities and prioritizing vital organs such as the heart and brain. Heart rate also reduces.

The way that the lungs compress under extreme water pressure, which doubles at a depth of just 33 feet compared to the ocean’s surface, also enhances the dive reflex. Paris says she has observed her heart rate drop below 40 beats per minute at extreme depth, compared to her normal resting rate of 60-plus beats.

She and other freedivers often describe an extraordinary calm and altered consciousness, similar to what is experienced during meditation, that kicks in after pushing past the discomfort of wanting another breath. “Everything slows down,” Paris says. Biologically, after the lungs strain for a bit to no avail, the spleen delivers a burst of oxygen-rich blood. That might contribute to the euphoric sensation. “Time doesn’t count anymore. It’s like being in another dimension basically,” Paris adds. “There have been moments where I come back up, and I just want to go back to that place where I was.”

Research indicates that the dive reflex, with long breath holds, especially activates the vagus nerve, a communication superhighway between our brain and nervous system. This vast nerve, which is really more of a meandering network, plays a key role in activating the relaxing parasympathetic nervous system. So freediving could be stimulating multiple feel-good sensations. But it’s dangerous Multiple diving sources cite a fatality rate around 1 in 500 for recreational freedivers.

Thankfully, you don’t have to take that plunge, or any risk, to flip the parasympathetic switch. Again, deep and slow breathing should do the trick.

Most of our daily lives are filled with rapid-fire stressors that trigger physiological responses in the body, including rapid breathing. It doesn’t require some scary predator like a lion or bear in pursuit to ramp up this sympathetic nervous system. Rush-hour traffic or an attack on social media can spark plenty of small-scale fight-or-flight reactions.

In this sense, Noble wonders if humans today have adapted to operate at a heightened state of stress, while the mind struggles to relax. He calls it a sympathetic bias. “We’re bent toward responding in a chronically stressed state,” he says. Perhaps our environment has influenced the average respiratory rate of 12 to 16 breaths per minute. When Noble considers that rate, he sees “someone who has adapted to the chronic stressors of the modern world.”

For context, the American Psychological Association announced “a national mental health crisis” in 2020, based only partially on the COVID- 19 pandemic. A Gallup poll three years prior showed that nearly half of Americans frequently face stress in their daily lives. And the medical world knows that chronic stress has been closely linked with chronic inflammation. This persistent swelling of white blood cells in the body has become a likely marker for early mortality, and a big contributor in a host of autoimmune diseases, such as asthma, rheumatoid arthritis and diabetes. Some more extreme breath practitioners, such as Dutch athlete Wim Hof, claim that breath work and cold exposure can treat many of these disorders.

The latest science does make a compelling case that prioritizing slow, deep breathing is one natural way to counteract inflammation, and a world predisposed toward stress. While it’s old news to practitioners of yoga and meditation or any tradition that values breath work, the measurable impact and data have been sparse in modern medicine over the years.

In late 2020, a team of scientists and physicians published a study that linked slow breathing with significant decreases in blood pressure and called for larger clinical trials. Mechanically, the researchers said the most likely connection between that deeper, slow breathing and blood pressure is the stimulation of the vagus nerve. The ongoing work could generate shifts in medical policies and treatments for reducing strokes, heart disease and, ultimately, mortality rates.

Of course, the work of science and scaling integrative medicine research can be methodical and slow going. So don’t hold your breath while waiting for more results.

Just think about slowing it down from time to time.

Tree Meinch is features editor at Discover. Follow @timeinch on Twitter.

My breath and mindfulness teacher got my attention, and respect, days before our session began: “Try to show up with an empty stomach (no food for two hours if possible).” The pre-session email also asked students about pregnancy, blood pressure issues or heart irregularities. This breath work sounded intense, and it is (inspired by kundalini and sattva yoga traditions). But these questions from Haley Niichel demonstrated she understood the power of breath, not only to heal and restore, but its potential for harm in people with particular conditions or risks. “This practice is NOT for pregnant mamas,” she emphasized.

This was in November of 2020, when my partner gifted me a 90-minute kriya and pranayama session online with her friend, a certified breath instructor. It seemed like a fun and healthy activity for the two of us who were becoming overly paranoid shut-ins in a new city mid-pandemic. We’d get through it, one breath at a time.

Via Zoom screen, Niichel led us through three seated breathing techniques that could be combined for a 15-minute-or-less daily practice. The first, known by some yoga practitioners as breath of fire, had us forcefully breathing through the nose with a contraction of the abdomen, ending with a long breath hold. The second involved rapid arm movements, with “mitten hands” raised like you’re about to start belting “it’s fun to stay at the Y” — then arm pumping in and out with sharp nose inhales and mouth exhales. We repeated this arm-and-breath dance for a couple of minutes. Eyes closed, shoulders burning, we sought a rhythm and tried to ignore how awkward we must have looked. The third technique was more calm and meditative: slow deep inhales and exhales, with subtle hand gestures called mudras on the lap.

For 90 minutes, Niichel watched us practice and encouraged us to take notes and drill her with questions. Then she sent us on our way. She asked that we commit to the practice daily for at least a week or two, and notice how we felt. More than six months later, I’ve only missed a handful of days and I have no plans to stop. Neither does my partner, who has reported relief in her neck after a decade of chronic pain and limited mobility.

While our observations are only anecdotal rather than data-driven, here’s what I’ve noticed:

• A reset: My daily practice reduces physical stress and mental anxiety (at least momentarily). I notice this especially when I do breath work over lunch on a workday. Similar to how waking in the morning can feel like a fresh start, worries that flooded into my morning become muted or disappear altogether during or at the end of a breath session. This seems to have generated more focus, energy and productivity in my days.

• Clarity: During the practice, as thoughts and emotions sink into the backdrop a bit, creative inspiration or focus often emerges. The title to this story, for example, effortlessly popped into my head while practicing — as did many of the words and ideas connecting the research and data in this piece.

• A Warm Buzz: Most days, during the third phase of my practice and for several minutes afterward, I feel a tingly yet heavy calm in my head and body. This differs from the decluttering described above. It’s a physical sensation, similar to the warm buzz some people feel after consuming a mind-altering substance.

• Sleep Routine: After years of failing to go to sleep at a decent hour and wake early (without feeling groggy), I settled into the best sleep routine of my adult life. This includes falling asleep regularly before midnight, and starting most mornings with a journaling exercise first thing upon waking.

While the practice above falls in the realm of intense breath work (and might pose health risks for some), Patricia Gerbarg, an integrative psychiatrist who specializes in breath practices, says that a technique called coherent breathing brings similar benefits. The goal is to inhale and exhale gently (ideally through the nose) at an even rate between four and six breaths per minute. Nearly anyone can safely practice this at any time to activate the rest-and-restore parasympathetic nervous system.

“It tells the brain, ‘the conditions are safe,’ ” Gerbarg says. “The less effort, the more you get out of this one.” — T.M.