Clinic and ambulatory blood pressure measurements for the evaluation of borderline hypertension in smokers and non-smokers.

Overview

Hypertension can be diagnosed only by blood pressure measurement, but conventional clinic measurement is subject to two major sources of error, first from the inherent variability of blood pressure, and second from the white coat effect, that is the increase of pressure that occurs in the presence of a physician. Ambulatory monitoring avoids both of these problems. Although smoking has been shown to raise blood pressure acutely, population studies have failed to show a sustained effect. To resolve this paradox, we compared clinic and ambulatory pressures in smokers and non-smokers. Clinic pressures were the same, but smokers had significantly higher daytime ambulatory pressures, than non-smokers, particularly in subjects over the age of 50. No differences in nighttime pressures were observed.