By Mary Carpenter
Mary Carpenter has covered breathing in recent MyLittleBird posts – in January of 2019 and of 2021. But recent reader queries about Breath the New Science of a Lost Art ($16.75) by James Nestor led to a different take on the topic, along with personally helpful advice.
“IF I HAD to limit my advice on healthier living to just one tip, it would be simply to learn how to breathe better”—naturopath and healer Andrew Weil, quoted in the Epilogue of James Nestor’s Breath.
In Breath Nestor links almost all bodily functions —along with possibilities for their improvement—to breathing. What the book does most helpfully is collect the research “all together in one neat package…along with an appendix of breathing exercises,” according to writeoutloud. To date, the book’s popularity has boosted sales of its recommended products—from the most inexpensive sleep strips to very pricey, personally fitted mouth retainers.
In Nestor’s self-improvement journey as a “pulmonaut,” he sometimes seems to go too far: as noted by one complainer on Amazon, “cure scoliosis by breathing through your nose…supposedly cure ADHD!” (To be fair, here Nestor is reporting other people’s experiences, not drawing conclusions.)
Among serious errors, Nestor confounds lung capacity and lung function—and incorrectly credits the Framingham Study with discovering that “greatest indicator of life span…was lung capacity…smaller [lungs] meant shorter [life].” In fact, many analyses of the Framingham data found that even “vital capacity” (the total amount of air you can forcibly expel from your lungs) was not a significant risk factor for heart disease.
But Nestor’s contentions about the health benefits both of breathing solely through the nose and of lengthening the exhaled breath have gained recent prominence. The nose warms and moistens the air, which improves its passage into the lungs, as well as slowing the breath.
And longer exhales make more room for incoming air, as well as slowing the breath to give the lungs more time to absorb oxygen. Exhaling through the nose can slow the breath by more than 50%, thereby lowering the respiratory rate (breaths per minute), writes Nestor.
While mouth breathing is usually faster and expels more carbon dioxide, nose-breathing decreases the ratio of oxygen intake to carbon dioxide output—seen in a recent study of 10 runners at Colorado State University. “You’re doing less work of breathing to get the same oxygenation,” said health sciences professor and the study’s lead author George Dallam.
Higher CO2 levels help dilate blood vessels to provide better transport for oxygenated blood and release oxygen from blood cells as they travel through the body—especially important for endurance. And CO2 buildup in the blood can stimulate the parasympathetic nervous system —as can lengthening the outbreath —to create a relaxing effect.
Nose-breathing “allows you to use your diaphragm better,” explains Dallam. Both diaphragm and lungs fall into the use-it-or-lose-it category: lungs lose an average of 12 percent of capacity between ages 30 and 50, and the loss continues over time. But individuals can expand their lung capacity—with the most extreme example being freedivers, who can increase theirs by 30 to 40%, according to Nestor.
“A typical adult engages as little as 10 percent of the range of the diaphragm when breathing,” writes Nestor, “which overburdens the heart, elevates blood pressure and causes of rash of circulatory problems.” Increasing the amount of air that enters the diaphragm can help slow the breathing and improve its effectiveness over time.
What also decreases with age is saliva production—by as much as 40% over age 65. Nestor rephrases this statistic to conclude that “mouth breathing causes the body to lose 40% more water”—but he focuses on its nighttime effects: exacerbating dehydration and, conversely, increasing the need to urinate.
Optimal slow breathing may be close to 5.5 breaths a minute, and some recommend adding a breath-hold. Among many formulae for this, for example, “box breathing” involves taking four seconds for the inbreath, four more to hold the breath, followed by four for the outbreath, with a final four-second hold.
Nestor advocates breath limitation techniques—extending exhales “far past the point of what feels comfortable, or even safe,” while reducing inhales. Also called hypoventilation, breathing too slowly or too shallowly to meet the needs of the body has helped athletes, notably swimmers, reduce their oxygen needs and improve performance.
Nestor also supports breathing methods originating in the practice of yoga, notably alternate-nostril breathing by closing one nostril at a time. Breathing through the left nostril alone can help with relaxation, via the parasympathetic nervous system—while breathing only through the right side of the nose activates the sympathetic nervous system to increase alertness and energy.
But Nestor’s most dramatic recommendations are aimed at correcting early dental work that, he contends, have damaged breathing in as many as half of orthodontic patients. Specific instructions for remedies include steps to improve “oral posture” and a complicated tongue-extending exercise called “mewing.”
What made the biggest difference for Nestor was the Homeoblock, a retainer-like device personally fitted to expand mouth size that he wore for a year, created by New York City orthodontist Theodore Belfor.
Along with more than a dozen “breathing methods” and exercises, Breath’s appendix lists devices, including Belfor’s “POD” (Preventive Oral Device) and other “palatal expansion” devices that “expand the palate and open airways.” Obtaining most of these requires consulting a dental professional, preferably one specializing in “functional orthodontics.”
On the lengthy list of personal health benefits for Nestor of better breathing: lower blood pressure and resting heart rate, higher heart rate variability (an indicator of cardiovascular fitness); increased blood CO2 levels, and reduced sleep problems (including snoring and apnea), along with specific improvements such as increased bone in the mouth and jaw areas, better aligned jaw position—widened airways—and greater exercise capacity.
My efforts to lengthen the exhale and to breathe solely through the nose seem to help with relaxation and sleep. But working on nose-breathing led me to Nestor’s drastic-sounding yet personally most useful recommendation: a thin strip of surgical tape to shut my lips at night. Besides seeming to make my sleep deeper and keep me from waking as often, enforced nose-breathing has been the best remedy so far for dry mouth, which always worsens in summertime.
—Mary Carpenter regularly reports on topical issues in health and medicine.