Abstract and Introduction
With aging there are changes in the cardiovascular system, which result in alterations in cardiovascular physiology. The changes in cardiovascular physiology must be differentiated from the effects of pathology, such as coronary artery disease, that occur with increasing frequency as age increases. The changes with age occur in everyone but not necessarily at the same rate, therefore accounting for the difference seen in some people between chronologic age and physiologic age. The changes in the cardiovascular system associated with aging are a decrease in elasticity and an increase in stiffness of the arterial system. This results in increased afterload on the left ventricle, an increase in systolic blood pressure, and left ventricular hypertrophy, as well as other changes in the left ventricular wall that prolong relaxation of the left ventricle in diastole. There is a dropout of atrial pacemaker cells resulting in a decrease in intrinsic heart rate. With fibrosis of the cardiac skeleton there is calcification at the base of the aortic valve and damage to the His bundle as it perforates the right fibrous trigone. Finally there is decreased responsiveness to
adrenergic receptor stimulation, a decreased reactivity to baroreceptors and chemoreceptors, and an increase in circulating catecholamines. These changes set the stage for isolated systolic hypertension, diastolic dysfunction and heart failure, atrioventricular conduction defects, and aortic valve calcification, all diseases seen in the elderly.
The process of aging is a continuum progressing throughout the individual's life. Unlike pathologic conditions, the aging process affects all individuals. It is a process that is genetically programmed but modified by environmental influences, so the rate of aging can vary widely among people. Therefore, physiologic aging in any given individual may occur more rapidly or more slowly than the chronologic age, giving rise to people who are "old" at age 60 and others who are "young" at age 75. The status of physical conditioning of the individual can radically affect the measurements of cardiovascular function in the elderly and changes in physical activity can profoundly change cardiovascular function.[1]
Physiologic aging is characterized by gradual loss in function in many organ systems. With aging there is also an increasing incidence of diseases such as coronary artery disease (CAD), cerebrovascular disease, renal, and pulmonary disease that can accelerate the loss of function. A major problem in human beings in measuring the effect of aging on cardiovascular physiology is that of eliminating the effects of latent disease in the population studied. This is illustrated by the prevalence of CAD in autopsy studies where over 60% of the patients dying at age 60 or older had at least one coronary artery that had a 75% or greater occlusion.[2] Since other studies find that about 20% of patients older than 80 years of age have clinically manifest CAD, the majority of older people with significant obstructive CAD are asymptomatic.[3] Therefore when evaluating the effect of age on cardiovascular physiology in a population of apparently healthy elderly people, those with latent CAD must be eliminated. In many studies reported in "healthy" elderly populations this has not been done and may account for discrepancies among studies reported on the effects of aging on cardiovascular function.
Am J Geriatr Cardiol. 2003;12(1) © 2003 Le Jacq Communications, Inc.
Cite this: Cardiovascular Physiology- Changes With Aging - Medscape - Jan 01, 2003.
