The Science of Breathing -
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The Science of Breathing

Your body breathes on autopilot—so why worry about how to inhale and exhale when you could be mastering an arm balance? For one thing, breath control, or pranayama, is the fourth of Patanjali’s eight limbs of yoga. For another, scientific research is showing that mindful breathing—paying attention to your breath and learning how to manipulate it—is one of the most effective ways to lower everyday stress levels and improve a variety of health factors ranging from mood to metabolism. “Pranayama is at once a physical-health practice, mental-health practice, and meditation. It is not just breath training; it’s mind training that uses the breath as a vehicle,” says Roger Cole, PhD, an Iyengar Yoga teacher and physiology researcher in Del Mar, California. “Pranayama makes your entire life better.”

Despite the inherently automatic nature of breathing, most people have a lot to learn and improve upon when it comes to the most basic of our physiological functions. We tend to huff at a fairly quick clip most of the time—anywhere from 14 to 2o breaths per minute is the standard, which is about three times faster than the 5 or 6 breaths per minute proven to help you feel your best, says Patricia Gerbarg, MD, assistant clinical professor of psychiatry at New York Medical College and co-author of The Healing Power of the Breath.

“There is a very direct relationship between breath rate, mood state, and autonomic nervous system state,” says Sat Bir Singh Khalsa, PhD, assistant professor of medicine at Harvard Medical School who studies yoga and meditation. The autonomic nervous system governs the body’s sympathetic (fight-or-flight) and parasympathetic (rest-and-restore) responses, dialing functions like heart rate, respiration, and digestion up or down as necessary in response to potential threats. Evolutionarily, this worked as a survival mechanism, but today’s nonstop barrage of smartphone pings, emails, and news updates also trips the body’s alarms—and often.

“We’ve long known that breath changes in response to emotion: When people get panicky and anxious, their breath becomes shallow and rapid,” says Khalsa. “But we now know from a number of really good studies that actively changing the breath rate can actually change autonomic function and mood state.”

Here’s how researchers think it works: With each breath, millions of sensory receptors in the respiratory system send signals via the vagus nerve to the brainstem. Fast breathing pings the brain at a higher rate, triggering it to activate the sympathetic nervous system, turning up stress hormones, heart rate, blood pressure, muscle tension, sweat production, and anxiety. On the other hand, slowing your breathing induces the parasympathetic response, dialing down all of the above as it turns up relaxation, calm, and mental clarity.

Ready to tap into the power of pranayama? We’ll teach you the ins and outs of O2 and CO2, so you can improve daily breathing both on and off the mat.

 

THE AIR CYCLE

“Getting rid of carbon dioxide, not bringing in oxygen, is the main stimulus that drives us to breathe under most circumstances,” Cole says. In other words, your body’s drive to boot what it doesn’t need is greater than its drive to acquire what it does. This is because too much CO2 makes the blood more acidic, which can impair the function of all of your body’s cells. Your brainstem is finely tuned to maintain the pH of the blood, so when the pH skews more acidic, it triggers the stress response and sends an urgent message to the diaphragm to initiate a breath to bring in more O2 and rebalance the blood.

Follow along to see what happens during one long, deep inhalation and exhalation.

On The Inhale

As you breathe in, the diaphragm (the dome-shaped muscle that primarily powers the breath) contracts, lowering and flattening. This increases the volume of the thorax (chest cavity enclosed by the rib cage), which not only makes room for the air coming into the lungs but also changes the atmospheric pressure inside the lungs, pulling air in. That air travels through your nostrils and into your nasal cavities, down through your pharynx (throat) and larynx (voice box), and into your trachea (windpipe). Next, it gets routed through the bronchi (passageways leading to the lungs) and bronchioles (passageways less than 1 millimeter in diameter) and into the lungs. Once in the lungs, the air reaches the alveoli (small air sacs), which serve as the marketplace for gas exchange: Oxygen (O2, the food your cells need to produce energy) is traded for carbon dioxide (CO2, the waste produced by energy production in cells) into and out of the bloodstream.

Simultaneously, as you inhale, your heart rate speeds up, thanks to a message sent by stretch receptors within the alveoli to the brainstem (controls heart rate) and the vagus nerve (commands autonomic function), increasing blood flow through arteries (tubes that carry blood away from the heart) to the lungs so more blood can be oxygenated.

From the alveoli, O2 molecules move into capillaries (thin-walled blood vessels) and attach to red blood cells, which start making their way through the pulmonary veins (vessels that carry oxygenated blood to the heart) to the left atrium, or chamber, of the heart. Next, blood moves into the heart’s left ventricle, which then contracts (beats). The contraction pumps oxygen-rich blood through every single cell in the body via the network of arteries and capillaries.

 

On The Exhale

Inside cells, mitochondria (the energy-production centres) use oxygen to burn sugars, fats, and proteins for energy, and CO2 is a byproduct of this process. CO2 is biochemical waste—you don’t need it—so your body starts the process of shuttling it out. CO2 travels through cell walls into the capillaries and then veins that carry CO2-rich blood to the right atrium and right ventricle of the heart. Next, the right ventricle contracts, pushing the CO2-rich blood out of the heart through the pulmonic valve into the pulmonary artery and back toward the lungs. As the blood enters the alveoli, the CO2 leaves the bloodstream and passes into the lungs. The diaphragm relaxes, decreasing the volume of and pressure in the thorax, and initiating an exhalation. Meanwhile, the heart rate slows, decreasing blood flow to the lungs and discouraging gas exchange while the lungs are still full of CO2-heavy air. The pressure change in the lungs forces the air and CO2 waste back up and out of the lungs into the trachea, through the larynx, pharynx, and nasal cavities, to be exhaled through the nostrils. Ahhh …

 

TAKE IT TO THE MAT

If you bypass breathwork on your yoga mat, you’re not alone.“Pranayama has really been left behind,” says Max Strom, yoga teacher and author of A Life Worth Breathing. He calls it a classic Cinderella story: Pranayama is often overlooked while the beautiful sister, asana, is the guest of honour at yoga studios. But give breathing a chance, and you’ll realise it’s the true queen, Strom says. Here, five transformative techniques.

 

Basic Breath Awareness

Begin by noticing where you already are with your breath, says Bo Forbes, PsyD, clinical psychologist and integrative yoga therapist. Do you know when and why your breath is shallow, or what makes it speed up? “This is really valuable information in creating stress resilience,” she says. Plus, just becoming aware of your breath tends to slow it down.

TRY IT  …  anytime, anywhere. Breathing through your nose, observe the inhalation and exhalation. Which happens faster? Which is longer? Don’t manipulate them. Just watch. Continue for 2–3 minutes.

 

Ujjayi Pranayama

(Victorious Breath or Ocean Breath)

This classic pranayama practice, known for its soft, soothing sound similar to breaking ocean waves, can further enhance the relaxation response of slow breathing, says Gerbarg. Her theory is that the vibrations in the larynx stimulate sensory receptors that signal the vagus nerve to induce a calming effect.

TRY IT … to focus your attention on your breath during asana. Inhale through your nose, then open your mouth and exhale slowly, making a “HA” sound.

Try this a few times, then close your mouth, keeping the back of your throat in the same shape you used to make the “HA,” as you exhale through the nose.

 

Nadi Shodhana Pranayama

(Alternate-Nostril Breathing)

This practice of alternating between the right and left nostrils as you inhale and exhale “unblocks and purifies the nadis, which in yogic belief are energy passages that carry life force and cosmic energy through the body,” Cole says. While there is no clear scientific evidence to support these effects, one pilot study found that within seven days of practicing this technique, overactive nervous systems were essentially rebalanced. And a study of 9o people with high blood pressure found Nadi Shodhana lowered blood pressure and improved mental focus.

TRY IT … at the end of an asana sequence to prepare the mind for meditation. Take a comfortable seated position. Close your right hand in a gentle fist in front of your nose, then extend your thumb and ring finger. Gently close your right nostril with your thumb. Inhale through your left nostril, then close it with your ring finger. Open your right nostril and exhale slowly through it. Inhale through the right nostril then close it. Open your left nostril and exhale slowly through it. That completes one cycle. Repeat 3–5 times.

 

Kumbhaka Pranayama

(Breath Retention)

If you inhale fully and then wait 1o seconds, you will be able to inhale a bit more, Strom says. Why? Holding your breath increases pressure inside the lungs and gives them time to fully expand, increasing their capacity. As a result, the blood that then travels to the heart, brain, and muscles will be more oxygenated.

TRY IT … after asana to prepare for meditation. Inhale, inflating the lungs as fully as possible. Hold the breath for 1o seconds. After 1o seconds, inhale a little more. Then hold it for as long as you can. One caveat: For anxious people, breath retention can be difficult. Strom suggests they start with holding the breath for 3 seconds, or as long as they’re comfortable, and work their way up.

 

Kapalabhati Pranayama

(Breath of Fire or Skull-Shining Breath)

This rapid breathing technique is energizing, and activates the sympathetic nervous system. In a study using EEG electrodes to measure brain activity, researchers found that Kapalabhati Pranayama increased the speed of decision-making in a test requiring focus. However, “For people already under stress, I don’t think Breath of Fire is a good idea,” Strom says. “You’re throwing gasoline on the fire.”

TRY IT … to jump-start your asana practice when youfeel lethargic, or for brainpower when you’re foggy.To start, take a full, deep inhale and exhale slowly. Inhale again, and begin exhaling by quickly pulling in the lower abs to force air out in short spurts. Your inhalation will be passive between each active, quick exhalation. Continue for 25–3o exhalations.

 

 

All Together Now

While priorities may differ between styles and teachers, when to inhale and exhale during asana is a fairly standardized practice element. Here, Cole offers three simple guidelines for pairing breath with types of poses.

 

When bending forward, exhale.

When you exhale, the lungs empty, making the torso more compact, so there is less physical mass between your upper and lower body as they move toward each other. The heart rate also slows on the exhalation, making it less activating than an inhalation and inducing a relaxation response. Since forward bends are typically quieting postures, this breathing rule enhances the energetic effects ofthe pose and the depth of the fold.

 

When lifting or opening the chest, inhale.

In a heart-opening backbend, for instance, you increase the space in your chest cavity, giving the lungs, rib cage, and diaphragm more room to fill with air. And heart rate speeds up on an inhalation, increasing alertness and pumping more blood to muscles. Plus, “Deep inhalation requires muscular effort that contributes to its activating effect,” Cole says. Poses that lift and open the chest are often the practice’s energizing components, so synchronizing them with inhalations takes optimum advantage of the breath’s effects on the body.

When twisting, exhale.

In twists, the inhalation accompanies the preparation phase of the pose (lengthening the spine, etc.), and the exhalation is paired with the twisting action. Posturally, that’s because as your lungs empty there’s more physical space available for your rib cage to rotate further. But twists are also touted for their detoxifying effects, and the exhalation is the breath’s cleansing mechanism for expelling CO2.

4 more reasons to BREATHE RIGHT

1 happiness + emotional stability

Manipulating the breath can alter how we feel, accounting for as much as a 40 percent variance in feelings of anger, fear, joy, and sadness, according to findings in the journal Cognition & Emotion. The breathing instructions used to evoke joy in the study? “Breathe and exhale slowly and deeply through the nose.” Sounds a lot like Ujjayi!

2 weight Loss

Yogic breathing practices increase levels of leptin, a hormone produced by fat tissue that signals the brain to inhibit hunger, according to research from Shirley Telles, PhD, director of the Patanjali Research Foundation in Haridwar, India.

3 Better exercise stamina

A cardiologist at the University of Pavia, Italy, compared a group of mountaineers who practiced slow breathing an hour a day for two years before attempting to climb Mount Everest to a group who didn’t. The breathing group reached the summit without needing the supplemental oxygen the other group did, and their blood and exhalation samples showed they were using 70 percent of the surface area of their lungs, an amount that maximizes the O2 taken in.

4 Longer life

Just one session of relaxing practices like meditation, yoga, and chanting influenced the expression of genes in both short-term and long-term practitioners, according to a Harvard study. Blood samples taken before and after the breathing practices indicated a post-practice increase in genetic material involved in improving metabolism and a suppression of genetic pathways linked with inflammation. Since chronic inflammation has also been associated with such deadly diseases as Alzheimer’s, depression, cancer, and heart disease, it’s probably fair to say that better breathing may not only change your life but may also save it.

 

Yoga Journal Senior Digital Editor Jessica Levine is relieved to know that when deadlines take priority over practice, several deep breaths can serve as a suitable substitute.

 

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