BACKGROUND: Syncope and falls are common in elderly persons and often result from the interaction of multiple clinical abnormalities. Both orthostatic hypotension and postprandial hypotension increase in prevalence with age. OBJECTIVE: To determine whether meal ingestion enhances orthostatic hypotension in elderly persons. DESIGN: Controlled paired comparison. SETTING: Clinical research center. PATIENTS: 50 functionally independent elderly persons recruited from local senior centers (n = 47) and from patients hospitalized with an unexplained fall or syncope (n = 3) (mean age, 78 years [range, 61 to 96 years]). Twenty-five participants (50%) were taking antihypertensive medication. MEASUREMENTS: Sequential head-up tilt-table testing at 60 degrees was performed before and 30 minutes after ingestion of a standardized warm liquid meal that was high in carbohydrates. Heart rate and blood pressure were continuously monitored. RESULTS: Meal ingestion (P < 0.01) and time spent upright (P < 0.001) were significantly associated with systolic blood pressure, but no significant interaction was found between meal ingestion and time spent upright (P > 0.2). These findings suggest that the association between meal ingestion and head-up tilt-table testing were additive and not synergistic. However, the proportion of participants with symptomatic hypotension increased during head-up tilt-table testing after meal ingestion (12% during preprandial testing and 22% during postprandial testing). Symptomatic hypotension tended to occur more often and sooner after meal ingestion than before meal ingestion (P = 0.03). CONCLUSIONS: Meal ingestion and head-up tilt-table testing are associated with increasing occurrences of symptomatic hypotension. After meal ingestion and head-up tilt-table testing, 22% of functionally independent elderly persons had symptomatic hypotension.