Acupuncture combined with low levels of electrical stimulation can lower blood pressure by up to 50% in animals, suggesting that it could be a good drug-free intervention for treating hypertension.
“This study suggests that acupuncture can be an excellent complement to other medical treatments, especially for those treating the cardiac system,” says study leader John Longhurst, director of the Susan Samueli Center for Integrative Medicine at the University of California, Irvine.
In previous studies, Longhurst and colleagues found at the cellular and molecular level how acupuncture excites brain cells to release neurotransmitters that either inhibit or heighten cardiovascular activity.
When acupuncture needles are inserted at specific sites on the wrist, inside of the forearm or leg, for example, it triggers the release of opioid chemicals in the brain that reduce excitatory responses in the cardiovascular system.
In their new study, Longhurst and colleagues applied acupuncture to points on the forelimb of rats with artificially elevated blood pressure rates. The points correspond to the inside of the forearm in humans, slightly above the wrist.
The researchers found that acupuncture alone had no effect on blood pressure.
When they added electrical stimulation to the treatment, however, running a current through the needles, the effect was dramatic. While high frequencies of stimulation had no effect, low frequencies lowered blood pressure by as much as 40% to 50%. And a 30-minute treatment had effects that lasted nearly two hours.