Autonomic and neurohumoral control of postprandial blood pressure in healthy aging

Background Postprandial hypotension (PPH) is a common and morbid problem in elderly people that is associated with an impaired Vascular response to me al digestion. Healthy aging in the absence of blood pressure elevation is a ssociated with autonomic and neurohumoral changes that may influence the va scular response to meal ingestion. However, it is not known whether these a ge-related changes are associated with the development of PPH Methods. We measured hemodynamic (blood pressure, heart rate, and forearm v ascular resistance), autonomic (power spectral analysis of heart rate and b lood pressure variability), and neurohumoral (plasma norepinephrine, renin, aldosterone, and endothelin) responses to a mixed 425 kilocalorie (kcal) m eal in 89 rigorously screened healthy subjects aged 20-39, 40-59, and 60-83 years. Results. After the meal, supine mean arterial blood pressure fell significa ntly only in the middle-aged group by 5.4 +/- 7.9 min Hg at 30 minutes (p = .02). Forearm vascular resistance fell after the meal in all age groups (p= .0001). Older groups had higher plasma norepinephrine (p =.02). lower heart rate (p =.03), lower cardiovagal activity (p =.0001), and lower sympatheti c vasomotor (p =.0001) activity, but there was no difference in the respons e of these variables to a meal. Conclusion. Healthy aging, in the absence of blood pressure elevation, alte rs the level of autonomic activity without further impairing the ability to maintain blood pressure during meal digestion. Hemodynamic, autonomic, and neurohumoral responses to meal ingestion remain unchanged in very healthy, normotensive elderly adults.