Differences between seated and recumbent resting measurements of auscultative blood pressure

Clinical blood pressure measurements conventionally have been taken while subjects are seated and at rest. FFA aviation medical examiners are required to measure blood pressure while the airman is in a recumbent position. Concern for possible positional differences in blood pressure values generated this study. Calibrated apparatus and objective methodology were used to record and measure blood pressure. Subjects consisted of 100 males between 20 and 60 years of age. Three blood pressure measurements were obtained for each body position. Measurement accuracy was to 2 mm Hg. Body-position order of measurement was randomized. Age and body-position order of measurement had no significant effect on body-position differences in systolic and diastolic pressure. For the total group, the average systolic and diastolic pressure were 6.6 and 0.8 mm Hg higher, repectively, in the recumbent position than in the sitting position. Although the former value was statistically significant, its practical application is obviated by the usual error of clinical measurement.