On the frequency and reproducibility of orthostatic blood pressure changes in healthy community-dwelling elderly during 60-degree head-up tilt.

The postural effects of 20 minutes of 60-degree head-up tilt on systolic, diastolic, and mean arterial blood pressures (BPs), heart rate, and rhythm were studied in 70 healthy, community-dwelling volunteer subjects of both sexes, divided into three age groups. Group A consisted of 30 subjects, with a mean age of 76 years (range 65 to 95 years); group B had 19 subjects, with a mean age of 54 years (range 45 to 64 years); and group C had 21 subjects, with a mean age of 33 years (range 24 to 44 years). To qualify, subjects had to have a systolic BP of 150 mm Hg or less and a diastolic BP of < 90 mm Hg, be taking no prescribed medications, have had no previous syncopal episodes, and have absence of any significant medical illness. Nine of 30 (30%) subjects in group A, 1 of 19 (5%) subjects in group B, and 2 of 21 (9.5%) subjects in group C exhibited asymptomatic postural drops in systolic blood pressure > 20 mm Hg (p < 0.05). The mean time for the systolic blood pressure drops in group A was 9.2 minutes. Results were reproducible upon retesting after 1 week.