Data on the benefits of Transcendental Meditation and biofeedback are weaker, with some studies showing effects and others not. Still, these methods may be worth a try, according to the statement. With biofeedback, patients monitor their blood pressure in real time while participating in a relaxation exercise or guided imagery. As for other forms of meditation, not enough evidence exists to recommend them.
Another exercise approach is isometrics, most commonly done with a hand grip device that is squeezed and held for several minutes. Some studies have reported impressive results — more than 10 mm decrease in systolic and nearly 8 mm in diastolic blood pressure. The caveat is that the studies are few and the number of participants small — 13 here, 42 there. The AHA statement said only that it “may be considered.”
Some doctors worry that isometrics’ sustained muscle contractions might be unsafe and lead to blood pressure spikes, Brook says, but studies reported no such ill effects.
“I was fascinated by the robustness of its effect on blood pressure,” Brook says. “It should get more focus, both in terms of effectiveness and safety.”
While meditation, relaxation techniques, acupuncture and yoga can provide many health benefits, there was no consistent evidence of their efficacy in reducing blood pressure. The AHA statement recommends against these practices for controlling blood pressure.
One thing is clear to doctors, Brook says: Different people respond to different things. The AHA statement focuses on average responses, but often a subset of people are very good responders. “We’ve all had patients who experience a 10 to 20 mm Hg drop” with a lifestyle change, he says. “But others have no improvement.”
Even with small effects, Brooks says, using Transcendental Meditation, exercise or device-guided breathing may help a person limit the dose or number of blood pressure drugs he or she must take.
The AHA statement offers doctors evidence-based tools beyond diet to recommend to their patients with high blood pressure, says Domenic Sica, a professor of medicine at Virginia Commonwealth University Medical Center in Richmond and soon-to-be president of the American Society of Hypertension.
“Not too many people will make dramatic changes in their lifestyle,” said Lawrence Appel, a doctor at the Johns Hopkins School of Medicine who worked on the AHA statement. “They inch in the right direction. They don’t go from five servings of veggies to 10, but maybe to six or seven. We hope that small benefits accrue from [multiple small changes] across several dimensions.”