Original article

Standing produces a pooling of blood in the peripheral circulation.1 This shift in compartmentalization reduces cardiac return to the heart and, consequently, stroke vol-ume and cardiac output. Nonetheless, under normal condi-tions, assuming an upright posture does not result in major changes in blood pressure (BP) due to complex integration of autonomic, circulatory, and neurohumoral responses.2 Orthostatic hypotension (OH) occurs in approximately 5 % of middle-aged adults in community-based studies.3–5 In elderly adults, the prevalence of OH is 16.2%,6 and increases further with age.7,8 Emerging evidence suggests that orthos-tatic BP changes are associated with poor cardiovascular out-comes due to stroke5 and coronary heart disease.9,10 Recently, measurement of upright BP, a simple maneuver, has shown that increased systolic BP (SBP) upon standing may provide a novel predictor of masked hypertension.11 Additionally, sub-jects with OH may display significantly more atherosclerosis risk factors including age, cigarette smoking, hypertension, diabetes mellitus, and hyperlipidemia.3 Upright tilt testing is the most common evaluation of orthostatic BP changes and autonomic fluctuations However, it may not be suitable for screening purposes in the general population.12 Simple upright standing requires few repeti-tions and does not stress subjects. However, few studies have examined its potential to evaluate cardiovascular disease risk in a large population. Increased age-related aortic stiff-ness is also an independent predictor of BP progression and hypertension and may result in a compromised buffer for BP fluctuations during postural changes. It remains unclear whether the role of aortic stiffness in the pathogenesis of OH is age-dependent.13 In this study of community-based, middle-aged, and elderly normotensive subjects, we evaluated orthostatic BP changes and autonomic nervous function using this simple testin