RACHEL MARTIN, HOST:
Millions of Americans take medicine for high blood pressure, and millions more are on the cusp of needing to do so. Now researchers in Colorado have new evidence that a device used during the pandemic to help COVID patients breathe better is also helpful in preventing high blood pressure and promoting good heart health for people at any age. Here's NPR's Allison Aubrey.
ALLISON AUBREY, BYLINE: During the early days of the pandemic, respiratory therapists who treated hospitalized COVID patients in the Netherlands started to experiment with a simple technique to help patients breathe better. Daniel Langer of University Hospital Leuven used it with patients coming off of ventilators and also in people who'd had mild COVID but still had shortness of breath.
DANIEL LANGER: What I asked the patient to do is to perform every day about five to 10 minutes of breathing exercises.
AUBREY: After a respiratory infection like COVID, some people lose strength in their breathing muscles, including the diaphragm. To help build it back, Langer prescribes a device that looks kind of like an inhaler. When patients breathe into it, the device provides resistance, making it harder to inhale.
LANGER: It's like a few sets of six to eight or 10 repetitions. We do the training, and we see that strength improves.
AUBREY: A randomized controlled trial showed the technique improved shortness of breath, and it turns out that the benefits are much, much broader. Researchers at the University of Colorado have just published a new study that shows strength training for your breathing muscles can improve measures of heart health and reduce blood pressure, even for young, healthy people. Here's exercise physiologist Daniel Craighead.
DANIEL CRAIGHEAD: Our respiratory function does decline as we age. So those muscles we use to breathe atrophy, just like the rest of our muscles.
AUBREY: In order to study how strength training for breathing muscles can influence heart health, Craighead and his colleagues recruited a bunch of participants to use the breathing trainer device called PowerBreathe. Their research is funded by the National Institutes of Health.
CRAIGHEAD: We found that doing 30 resisted breaths per day for six weeks will lower systolic blood pressure by about 9 millimeters mercury. And those reductions are at least as large as what we see with conventional aerobic exercise, like walking, running or cycling.
AUBREY: One way this works has to do with the endothelial cells which line our blood vessels. These cells help produce nitric oxide, which widens the blood vessels and helps prevent the buildup of plaque in our arteries. It's long been known that diaphragmatic or meditation breathing can help lower blood pressure, and Craighead says the benefits of this technique that he refers to as IMST is that it takes less time to get the benefit.
CRAIGHEAD: What we found was that six weeks of IMST will increase endothelial function by about 45%. So that suggests that in the long term, people would have a much lower cardiovascular disease risk.
AUBREY: Follow-up studies will help determine how long the effects hold up, and physician Michael Joyner of the Mayo Clinic says the results are promising so far.
MICHAEL JOYNER: I think promising for several reasons. I think it's promising because of the simplicity of the technique and also the magnitude of the effect. If you start seeing reductions in blood pressure of, you know, 5 millimeters or five points or six or seven or eight, that's the type of reduction you see with a drug, an anti-blood pressure drug.
AUBREY: Breathing training may not replace blood pressure medications for people at high risk, nor is it a replacement for exercise, which has many other benefits. But it is a technique that, if added as a daily habit, could help to reduce the risk of heart disease. That's the way 61-year-old Theresa Hernandez, who has high blood pressure in her family, sees it. She participated in the Colorado study and did the training with the PowerBreathe device for six weeks.
THERESA HERNANDEZ: It was a surprise that something as simple could be so profound in terms of its impact.
AUBREY: Her blood pressure dropped, and her endothelial function improved significantly. Now the researchers want to explore potential benefits for endurance athletes, such as cyclists and long-distance runners who want to improve their performance.
Allison Aubrey, NPR News.
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