To the Editor.
—We wish to comment on the article by Blumenthal et al1 that found that moderate aerobic exercise does not lower blood pressure in persons with untreated mild hypertension. We recently have reviewed the literature on physical activity and blood pressure and almost all the studies show that physical activity lowers blood pressure in spite of the majority of articles having major design flaws. Although there may be a publication bias toward studies with positive results, we believe that the study by Blumenthal et al has numerous design limitations that may explain its unusual findings. The major problems are potential contamination of the control group, cointervention of the intervention group, and lack of blind assessment of blood pressure measurement.With the passage of time, the loss of the alerting response (white-coat effect) results in a reduction of blood pressure in control groups. Also, the waiting-list participants would have
Arroll B, Beaglehole R, Hill D. Failure of Exercise to Reduce Hypertension. JAMA. 1992;267(13):1777. doi:10.1001/jama.1992.03480130088021