The inexorable increase in the number and proportion of elderly people in Western countries and their disproportionate utilization of health care resources has fueled interest in gerontology and geriatrics [1]. On the clinical side, a body of important scholarship hasfocused on the organization and financing of long-term care services, the risks for institutionalization, etc. But despite heavy utilization by the elderly of acute care services, especially in hospitals, study of the acute care needs of the elderly has been less intensive and strategies devoted to health promotion and disease prevention have been relatively neglected. Somehow advanced old age is not seen as the appropriate place for prevention. This is unfortunate, since the dramatic increases in life span in this century now provide both a challenge and an opportunity for increases in health span and decreases in morbidity. If our goal is to enhance active life expectancy, initiatives to reduce morbidity and increase function are clearly needed. On the biomedical research scene, there has been a major emphasis on identifying and explaining the influence of 'normal aging' in the absence of disease. The rationale for this body of work emphasizes that the physiologic changes that accompany aging may influence the presentation of disease, its response to treatment, and the complications that ensue. Numerous carefully conducted cross-sectional and longitudinal studies of this type have demonstrated major effects of age on a number of clinically relevant variables, including pulmonary function, renal function, and immune function [2, 3]. In much of this work, investigators have carefully excluded individuals identified as having diseases and have thus lumped the remaining individuals into a large category of 'normal aging'. This dichotomy of findings into 'disease-related' versus 'normal aging' phenomena, which has dominated the field, has important limitations. It neglects the sustantial heterogeneity amongst older persons with regard to many physiological variables and implies that the physiological changes that occur in older individuals, in the absence of disease, are harmless and do not carry significant risk [4]. In short, the tendency to define these changes as 'normal' suggests that they represent the natural state of affairs and thus should not or cannot be modified. However, recent research suggests that the physiological changes that occur with 'normal age', in the absence of disease, are highly variable, in many cases are associated with