Longitudinal changes in the blood pressure responses to, and gastric emptying of, an oral glucose load in healthy older subjects.

Abstract

The rate of gastric emptying is a major determinant of the hypotensive response to a meal. Cross-sectional studies suggest that healthy aging is associated with a modest slowing of gastric emptying. We aimed to determine longitudinal changes in the BP response to, and gastric emptying of, glucose in healthy older people. 33 participants (77.0±0.7yr) had baseline and follow-up measurements after 5.8±0.1yr. Participants consumed a 300mL drink containing 75g glucose and 150mg C 13-acetate. BP and heart rate (HR) were measured at 5-min intervals for 120min after the drink. Exhaled breath was collected to calculate the gastric 50% emptying time. The prevalence of postprandial hypotension (PPH) doubled from 9.1% to 18.2%. Gastric emptying was slower at follow-up (P=0.04). The fall in systolic BP (SBP) was related directly to the rate of gastric emptying at both the initial study (r=0.54, P=0.005) and at follow-up (r=0.41, P=0.04). The change in the maximum fall in SBP was related to the increase in baseline SBP (r=-0.63, P<0.001). In conclusion, in healthy older people over a period of ~5.8yr, there was an increased prevalence of PPH and a modest slowing of gastric emptying. The latter was related directly to a greater hypotensive response.