Muscle Mass and Breathing

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STRENGTHENING muscles was never of much interest to DC-based writer WZ so long as she could do the daily aerobic exercise she enjoyed, especially swimming—until she had pulmonary testing to investigate mild shortness of breath—dyspnea.  When results of lung testing—many rounds of spirometry (blowing out strenuously into a tube)—were good, two other possible explanations did not apply: she was not obese, and her heart was fine.

That, according to the pulmonologist, left the muscles. As lung function and capacity can decline with age, muscles like the diaphragm get weaker, and oxygen capacity decreases. Conversely, optimal breathing capacity correlates with lung volume as well as with upper extremity strength —and expiratory muscle strength training has led to improved breathing ability. Sarcopenia, first used in 1989 to describe progressive loss of skeletal muscle mass (SMM) with advancing age, now more commonly refers to impaired muscle strength for any reason —which can include chronic conditions like diabetes. And while it most often occurs with age, sarcopenia may worsen with inflammation, such as that occurring with osteoarthritis.

Skeletal muscle mass—important for mobility, balance and strength—differs from “lean body mass,” which includes bones, connective tissue and bodily fluids in addition to muscle mass. To combat diminished SMM, resistance weight training and upping protein consumption are the most common recommendations, as are breathing exercises if weakened diaphragm muscles restrict activity or cause other problems.

One reason for assessing SMM: when added to decreases in bone density, sarcopenia may double the risk of osteoporosis and the corresponding likelihood of bone fracture in women—and may also contribute to insulin resistance and the risk of diabetes.

The same DEXA (dual-energy X-ray absorptiometry) scans that assess bone density may also provide the best measurements of muscle mass, although other scans like CT and MRI also work well. But most physicians consider scans for muscle mass scans insufficiently useful to justify the radiation involved —thus reserving them for suspected muscle degeneration diseases, like muscular dystrophy, or malnutrition, WZ’s internist explained.

Methods for assessing muscle mass that do not involve radiation, on the other hand, are less accurate because they rely on estimates from standard prediction equations rather than making direct measurements, and in many cases use prediction formulas that are inaccurate.

The “gold standard” assessment of the past, underwater weighing, measured displacement—with subjects required to “expel as much air as possible from their lungs and sit completely submerged in a tank of water, a process that may be repeated several times.”

More recently, bioelectrical impedance analysis (BIA)—used, for example, by “body fat scales”—sends a weak electrical impulse through the body that encounters varying levels of resistance (impedance) to detect fat, which creates more resistance than muscle or water. Although some BIA assessments have correlated well with those made by DEXA scans, readings in a 2016 evaluation of six body-fat scales by Consumer Reports were off by anywhere from 21% to 34%.

The device against which Consumer Reports made its comparisons, the Bod Pod, is another “displacement” method like underwater weighing, but its sensors detect air pressure changes that reflect the volume of air displaced by body. Despite sharing a high margin of error—because these also use formula-based estimates instead of direct measurement—both the scales and the Bod Pod can help keep track of losses or gains in muscle mass over time.

For combating decreased muscle mass, many turn to protein supplements—based on evidence that adults over 50 benefit from eating as much as twice the RDA. In one study, the group who consumed 25% of calories from protein had lower blood pressure and harmful LDL cholesterol levels; in another, those who doubled their protein RDA built more muscle than they were losing.

Another popular supplement to counter low muscle mass is creatine—produced by several organs and stored in muscles throughout the body—which plays an important role in physical performance and muscle growth.  On the other hand, both supplements have had mixed results, “despite a huge amount of research.”

Some research has also linked regular doses of anti-inflammatories to improved muscle mass, but there are many caveats and downsides to the ongoing use of these.

And although aerobic exercise can help support muscle growth and slow its loss, those exercises that specifically target increasing muscle mass for improved breathing include: bodyweight exercises like pushups and planks; resistance-band exercises; free weights; and Pilates.

In studies on select groups such as smokers, those who added 30 minutes of UBRT (upper-body resistance training) to 10 minutes of breathing exercises— using a spirometer—improved their measurements of lung health.

Focused solely on breathing, the most commonly recommended exercises work best with modifications that involve gentle breath and movements, according to Rebecca Carli, whose DC area Rolfing-based body-work practice has helped WZ over decades and who recommended Carola Speads’s book Ways to Better Breathing.

For “pursed-lip breathing,” sit upright in a chair; inhale; then exhale briefly before bringing a drinking straw to the mouth, between pursed lips, without bending forward; and continue exhaling. To be sure all air is passing through the straw, use a nose clip during the first few exhales; leave a little breath at the end for a final, unforced exhale; and after each exhalation through the straw, take time out to allow the breath to respond freely.

“Belly breathing,” also called “diaphragmatic breathing,” starts with lying flat and exhaling. Then, instead of the common advice of placing one hand on the lower abdomen to feel the in-breath expand there, focus instead on allowing the breath to fill the lower back or sacral area. At first, do each exercise for five minutes—and slowly add on as breathing becomes easier.

Reluctant to add muscle mass to WZ’s next DEXA scan prescription, her internist had a different suggestion—addressing the shortness of breath with “some pulmonary rehabilitation, once the Covid situation is improved.”

—Mary Carpenter

Mary Carpenter regularly reports on topical issues in health and medicine.