Washington – Take a slow, deep breath, then exhale just as slowly. Can you take fewer than 10 breaths a minute? Research suggests breathing that slowly for a few minutes a day is enough to help some people nudge down high blood pressure.
Why would that brief interlude of calm really work? A scientist at the National Institutes of Health thinks how we breathe may hold a key to how the body regulates blood pressure – and that it has less to do with relaxation than with breaking down all that salt most of us eat.
Dr. David Anderson is trying to prove it, with the help of a gadget that trains volunteers with hypertension to slow-breathe.
If he’s right, the work could shed new light on the intersection of hypertension, stress and diet.
“If you sit there under-breathing all day and you have a high salt intake, your kidneys may be less effective at getting rid of that salt than if you’re out hiking in the woods,” said Anderson, who heads research into behavior and hypertension at the NIH’s National Institute on Aging.
While they know risk factors – being overweight and inactive, and eating too much salt – scientists don’t fully understand the root causes of hypertension.
Enter breathing.
In 2002, the Food and Drug Administration cleared the nonprescription sale of a medical device called RESPeRATE, to help lower blood pressure by pacing breathing. The Internet-sold device counts breaths by sensing chest or abdominal movement, and it sounds gradually slowing chimes that signal when to inhale and exhale. Users follow the tone until breathing slows from the usual 16 to 19 breaths a minute to 10 or fewer.
In clinical trials funded by maker InterCure Inc., people who used the slow-breathing device for 15 minutes a day for two months saw their blood pressure drop 10 to 15 points. It’s not supposed to be a substitute for diet, exercise or medication but an addition to standard treatment.
So, in a laboratory at Baltimore’s Harbor Hospital, Anderson is using the machine to test his own theory: When under chronic stress, people tend to take shallow breaths and unconsciously hold them, what Anderson calls inhibitory breathing. That knocks off kilter the blood’s chemical balance. More acidic blood in turn makes the kidneys less efficient at pumping out sodium.
