The Influence of Oral Glucose Loading on Baroreflex Function in the Elderly

Blood pressure in the elderly may decrease after a meal or after oral glucose loading. It has been suggested that eating may affect blood pressure homeostasis through an insulin-induced blunting of baroreflex sensitivity. We investigated the effects of oral glucose loading on baroreflex sensitivity in young normotensives and in elderly normo-and hypertensive subjects. Blood pressure was measured by a new noninvasive device, Finapres, which measures blood pressure continuously in the finger. Baroreflex sensitivity was estimated with the phenylephrine and nitroglycerin method. In both elderly groups mean arterial pressure fell significantly after the glucose load (11 +/- 1 mm Hg, P less than .001 in the hypertensives, and 8 +/- 2 mm Hg, P less than .01 in the normotensive subjects), whereas no change in blood pressure was found in the young group. Baroreflex sensitivity was lower in both elderly groups than in young normotensives. Glucose loading had no influence on baroreflex sensitivity in the three groups. Therefore, we conclude that other factors are involved in the phenomenon of postprandial hypotension in the elderly.