Assessment of Autonomic Nervous Function in Elderly Subjects with or without Postprandial Hypotension.

50 elderly subjects with or without postprandial hypotension (defined as a reduction of more than 20 mmHg in systolic blood pressure after a meal)

Non-invasive assessment of autonomic nervous function (head-up tilt, cold pressor test, hyperventilation test, and mental arithmetic test)

Elderly subjects without postprandial hypotension

Autonomic nervous function responses including heart rate response to systolic blood pressure reduction, coefficient of variation of R-R intervals, and deltaSBPsurrogate