Q. How low should your blood pressure go? Doctors have a surprisingly hard time answering this seemingly simple question.
A. In the mid-20th century, what doctors accepted as natural blood-pressure readings that would terrify today’s physicians. A pre-eminent cardiologist, Dr. Charles Friedberg, wrote in his popular textbook that mild benign hypertension, which he counted as blood pressure up to 210/100, did not require treatment (Journal of Clinical Hypertension, Suppl. 8, August 2006).
By the 1960s and 1970s, though, data from the Framingham Heart Study suggested that getting blood pressure down from that level could save patients from suffering kidney damage, congestive heart failure and stroke. Doctors also had more and better blood-pressure medications to prescribe, and thus began the downward drift of standards for where blood pressure “should” be.
The first guideline was published by the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure in 1977. It recommended treatment if diastolic blood pressure (the second and lower number) went to 105.
By 2003, the official guideline was that hypertension started at a blood pressure of 140/90. Blood pressure over 120/80 was considered prehypertension. Soon, many doctors started prescribing pills for people diagnosed with prehypertension.
Then in 2012, the Cochrane Collaboration published a meta-analysis of randomized controlled trials of blood-pressure treatment (Cochrane, Aug. 15, 2012).
After reviewing the evidence, these experts concluded that treating otherwise healthy adults with blood pressure ranging from 140-159 (systolic) or 90-99 (diastolic) did not save lives or prevent heart attacks and strokes. They noted that blood-pressure medication does have side effects and called for more research to determine “whether the benefits of treatment exceed the harms.”
Then in 2015, a large study of blood-pressure treatment was stopped early with much hoopla because the results were so good (New England Journal of Medicine, Nov. 26, 2015).
The SPRINT study found that getting systolic blood pressure down to 120 or lower reduced the risk of a heart attack. That is wonderful news, but keep in mind that 172 people needed to be treated intensively for three years to prevent one death.
What should we make of this hypertension confusion? There is no doubt that lower blood pressure is better than higher blood pressure, but how that’s achieved may make a difference. Blood-pressure medicine can cause side effects including dizziness, fatigue, forgetfulness, impotence, cough and swollen legs.
Lowering blood pressure through diet, exercise and weight loss offers a safe alternative for many people. Our Guide to Blood Pressure Treatment describes the DASH diet that has been scientifically tested and shown to lower blood pressure, along with other non-drug approaches. Anyone who would like a copy, please send $3 in check or money order with a long (No. 10), stamped (71 cents), self-addressed envelope to: Graedons’ People’s Pharmacy, No. B-67, P.O. Box 52027, Durham, NC 27717-2027. It also can be downloaded for $2 from our website, peoplespharmacy.com.
Certain foods, such as beets, chocolate, Concord grape juice, kefir and pomegranate, also hold promise for blood-pressure control without the side effects that blood-pressure medications may cause.
Joe Graedon is a pharmacologist; Teresa Graedon holds a doctorate in medical anthropology and is a nutrition expert. The People’s Pharmacy radio broadcast airs at 2 p.m. Saturdays on WBFO-FM 88.7.