New evidence suggests that a daily muscle-strengthening routine for the diaphragm and other "breath training" efforts help boost heart health and decrease high blood pressure, Allison Aubrey writes for NPR's "Shots."

Slide deck: Cardiovascular market trends for 2022

The benefits of daily breathing exercises

According to Daniel Craighead, a study researcher and an integrative physiologist at the University of Colorado Boulder, "[t]he muscles we use to breathe atrophy, just like the rest of our muscles tend to do as we get older."

To see if a workout routine would strengthen these muscles, Craighead and his colleagues recruited a group of healthy volunteers from age 18 to 82to participate in a daily five-minute exercise with a resistance-breathing training device called PowerBreathe—a hand-held device that looks like an inhaler.

When people breathe into the device, it provides resistance, which makes it more difficult to inhale.

"We found that doing 30 breaths per day for six weeks lowers systolic blood pressure by about 9 millimeters of mercury," Craighead said. The improvements mirror the expected effects of conventional aerobic exercises, including walking, running, or cycling.

"That's the type of reduction you see with a blood pressure drug," said Michael Joyner, a physician at the Mayo Clinic who studies how the nervous system regulates blood pressure.

"Research has shown many common blood pressure medications lead to about a 9 mmHg reduction," Aubrey writes. "The reductions are higher when people combine multiple medications, but a 10 mmHg reduction correlates with a 35% drop in the risk of stroke and a 25% drop in the risk of heart disease."

Daily respiratory strength training also helps regulate blood pressure. According to Craighead, endothelial cells line blood vessels and promote nitric oxide production, which helps widen blood vessels, promote blood flow, and prevents plaque buildup in the arteries. "What we found was that six weeks of IMST [inspiratory-muscle strength training] will increase endothelial function by about 45%," Craighead said.

Respiratory strength training may have benefits no matter your age

The new evidence suggests that IMST can benefit adults of all ages. "We were surprised to see how ubiquitously effective IMST is at lowering blood pressure," Craighead said.

"I think it's promising," Joyner said about using strength training as a preventive measure for respiratory muscles. "Taking a deep, resisted, breath offers a new and unconventional way to generate the benefits of exercise and physical activity," Joyner wrote in an editorial published alongside a study in the Journal of the American Heart Association.

Before his team got the test results back, Craighead said he suspected that young, healthy adults might not see much of a benefit from IMST. "But we saw robust effects," he said, citing a significant drop in blood pressure across all participants. According to Craighead, the finding suggests IMST could help healthy young people stave off heart disease and increased blood pressure, which often occurs with aging.

In addition, Craighead noted that IMST may benefit endurance athletes. For example, six weeks of IMST increased aerobic exercise tolerance by 12% among middle-aged and older adults.

"So we suspect that IMST consisting of only 30 breaths per day would be very helpful in endurance exercise events," Craighead said.

Joyner also shared that people who cannot engage in conventional aerobic exercises could benefit from respiratory strength training. He highlighted the appeal of the device's simplicity since people can easily use it at home.

While the technique is not meant to replace exercise or medication, "it would be a good additive intervention for people who are doing other healthy lifestyle approaches already," Craighead added. (Aubrey, NPR, "Shots," 9/20)