Blood pressure variability and reflex control in the elderly

Several lines of experimental and clinical evidence collected over the past ten years suggest that the aging process is characterized not only by profound structural cardiovascular alterations, but also by marked functional changes in the reflex mechanisms involved in the homeostatic control of the circulation. This paper will examine how aging affects baroreceptor control of the heart and sympathetic nerve traffic, providing evidence that while the former is markedly impaired in the elderly, the latter is virtually preserved. It will also discuss the age- related alterations in cardiopulmonary receptor function that, under physiological conditions, tonically inhibit sympathetic vasoconstriction tone and renin release from the kidney. Finally, evidence will be provided showing that short- and long- term blood pressure variabilities (and the different components of blood pressure variability) over 24 hours undergo major changes in the elderly. All these alterations in neural cardiovascular control mechanisms have clearcut clinical implications representing a potential marker of the increased cardiovascular risk which characterizes elderly people.