Harvard Heart Letter

Heart Beat: Big bend for blood pressure?

Heart Beat

Big bend for blood pressure?

Subtle, precise nudges of a misaligned atlas can dramatically lower blood pressure. We are not talking about rearranging reference books, but about lining up the spinal column's topmost vertebra.

The C-1 vertebra is a doughnut-shaped bone at the top of the spine. It is sometimes called the atlas vertebra because it supports the head, much as the titan Atlas held up the sky in Greek mythology. Unlike the 25 vertebrae below it, which maintain their positions by nestling one into the other, the atlas is held in place mostly by muscles and ligaments. A link between a misaligned atlas and high blood pressure has been known since the 1960s. Now, a Chicago-area team has tested whether realigning a skewed atlas could improve blood pressure. It was headed by Dr. George Bakris, an eminent hypertension expert at the University of Chicago who helped write the national guidelines for blood pressure treatment.

Fifty volunteers with modest high blood pressure and a misaligned atlas vertebra volunteered for the trial. Half had the bone gently nudged into place by a chiropractor who specialized in adjusting this one vertebra. The other half, the placebo group, received a manipulation that let the atlas remain cockeyed. After eight weeks, systolic blood pressure had fallen by 3 millimeters of mercury (mm Hg) and diastolic pressure by 2 mm Hg in the placebo group, suggesting a small placebo effect. In the realignment group, systolic blood pressure dropped a whopping 17 mm Hg and diastolic an equally impressive 10 mm Hg. Those are substantial improvements in blood pressure, far surpassing what is usually seen in tests of single blood pressure medicines. The results were published in the Journal of Human Hypertension.

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