In a randomized controlled trial from the University of Colorado Boulder, adults who inhaled through a hand-held resistance breathing device for about five minutes a day lowered their systolic blood pressure by roughly 9 mmHg after six weeks.
The routine is called inspiratory muscle strength training, or IMST, and the drop it produced rivals what many first-line blood pressure drugs achieve. The trial results were published in the Journal of the American Heart Association in June 2021.
Participants were 36 adults ages 50 to 79 with above-normal systolic pressure. Half performed 30 forceful inhalations a day, six days a week, against 75 percent of their peak inspiratory strength using a resistance trainer called PowerBreathe. The rest used a sham device with minimal resistance.
A brief, hard-breathing session
Each session took roughly five minutes and looked nothing like the slow, calming breathwork most people picture. The University of Colorado Boulder team framed it as a workout for the diaphragm. Adherence hit 95 percent, and no dropouts were reported.
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"IMST can be done in five minutes in your own home while you watch TV," said Daniel Craighead, assistant research professor in the Department of Integrative Physiology at CU Boulder.
Beyond the systolic drop, researchers reported a 45 percent improvement in vascular endothelial function, higher nitric oxide levels and reductions in oxidative stress. Nitric oxide is the signaling molecule blood vessels use to relax and widen.
Confirmed across five trials
A pooled analysis of five randomized, sham-controlled trials, published in 2022 in the Journal of Applied Physiology, drew on 128 adults aged 18 to 82. The IMST group again lost about 9 mmHg of systolic pressure and 4 mmHg of diastolic pressure over six weeks, with no adverse events reported. Older adults tended to see the largest drops.
For context, the American College of Cardiology and American Heart Association classify a reading of 130/80 mmHg or higher as stage 1 hypertension. Sustained reductions of even a few mmHg meaningfully lower long-term risk of heart attack and stroke.
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Why the diaphragm workout may help
The proposed mechanism is straightforward. Repeated inhalations against heavy resistance train the diaphragm and rib cage muscles, and appear to boost nitric oxide bioavailability in the lining of blood vessels. Better endothelial function means arteries relax more easily, which lowers the pressure pushing against their walls.
The pooled analysis noted that blood pressure benefits did not depend on how much respiratory muscle strength participants gained. Something about the training itself, rather than raw diaphragm power, seems to drive the vascular effect.
What this does not replace
The researchers frame IMST as a possible add-on, not a substitute for prescription therapy. In the CU Boulder data, participants already on blood pressure medication saw smaller diastolic reductions than those who were medication-naive. Anyone considering the technique should talk with a doctor first, especially if they already take antihypertensives or have a serious heart or lung condition.
Hand-held resistance breathing trainers such as PowerBreathe are widely available online and at pharmacies. The trial protocol used a device set to 75 percent of the user's peak inspiratory pressure, a level that generally requires guidance from a clinician or a device that can be calibrated. Starting at a lower resistance and building up is a common approach.
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The evidence base is still modest. The signature finding rests on one small randomized controlled trial and a retrospective pool of related trials from the same research group, and larger, independent replications are underway.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.