Systemic hemodynamics and aging

The influence of advancing age on cardiovascular function has been the subject of many studies in the last few years. The increase of average life span and proportion of old people in the general population stimulated a number of studies in order to obtain a deeper knowledge of the normal physiology of aged individuals. Cross-sectional and longitudinal studies are used to examine the effects of aging. Both type of studies have some drawbacks. The cross-sectional study is planned to analyze at one time a group of individuals of different ages. In such study, it is difficult to eliminate genetic or environmental differences among groups. Furthermore, the older groups may represent a selected long-lived subset of the younger population. A longitudinal study examines the same individuals as their age advances and, therefore, a very prolonged time is required for studying humans. In such a study among many other obvious obstacles, an important one is the possible changes in methodology, not always easy to differentiate from age changes. In any case, the extent to which these studies may analyze the normal aging process is determined by the level of certainty regarding the absence of disease. This requirement can be difficult to be met, owing to the prevalence of atherosclerosis or occult coronary disease in the old age [1].