Exercise, Functional Decline and Frailty

Age-related decline in physiologic function is familiar to anyone interested in aging. Physicians observe gradual declines in their patients. Most people notice subtle changes themselves. For most of a person's life, age-related decline has little functional significance, except perhaps for elite athletes. Eventually, however, because of its apparent relentless, year-in-year-out pace, decline in physical performance will produce functional impairment and can add to the morbidity of chronic diseases. The past decade has witnessed increased interest in maintenance of functional capacity as shown by influential papers dealing with topics like compression of morbidity1, 2 and active life expectancy.3 Because exercise, especially exercise designed to produce physical conditioning, is known to improve physical performance, there is great interest in the role of exercise as a means to forestall or attenuate age-related decline and prevent or treat frailty.4 The paper by Morey et al5 provides important information about the duration of improvement that occurs from exercise training. Longitudinal data are needed to know whether exercise has an effect on age-related decline in performance.4 Previously, the only available data consisted of a few reports comparing maximal oxygen consumption in small numbers of sedentary and habitually active persons over time.6-8 Based on these studies, we concluded that for middle-aged men, regular exercise might decrease the rate of age-related decline by half but that more data were needed, especially in older persons where decline has more functional significance.4, 9 The study by Morey et al demonstrates that gains in cardiovascular performance and flexibility can be sustained for 2 years. Strength, although not significantly improved, increased somewhat and definitely did not decline. Overall, Morey's report provides additional supportive evidence that habitual and, if necessary, supervised exercise can play an important role in maintaining functional capacity. Two papers, one describing functional morbidity10 and the other describing the effect of vigorous muscle strengthening programs,11 point out the likely relationships between frailty, illness, bedrest, and exercise. Hirsch et al10 described the “natural history of functional morbidity” in 71 unselected elderly hospitalized patients, mean age 84, admitted to a university hospital. From baseline (2 weeks before admission) to hospital day 2, overall function declined, as did individual scores for mobility, transferring, toileting, feeding, and grooming. Between day 2 and discharge, 65% showed no improvement, and 10% deteriorated even further. The decline in mobility was striking: on discharge, the majority of patients were dependent in mobility, and of these, 70% (30 of 43) had originally been completely independent at baseline. Whether these patients recovered functional independence is not reported. We also do not know the extent to which recovery from the functional morbidity of acute hospitalization is possible. Nonetheless, the morbidity associated with hospitalization is considerable. A recent paper by Fiatarone et al11 provides evidence about the potential for frailty to improve. The paper also provides insights about how to approach the functional morbidity10 associated with acute illness. She and her colleagues found that high intensity strength training in frail persons whose average age was 90 resulted in impressive gains in muscle strength (average gain = 174%) and coexistent improvement in functional mobility, including a 48% increased tandem-gait speed. These gains occurred after an 8-week, three-session-per-week training period. Such gains almost certainly would translate into improved functional capacity and independence. Thus, convincing evidence of the therapeutic efficacy of exercise is developing for two groups of older patients. In frail elderly, programs of fairly vigorous high intensity strength training translate into real gains in muscle strength and functional mobility. For persons who are not in the “frail” category but are likely to experience age-related functional decline, exercise programs such as those described by Morey et al5 appear to offer benefits that are sustained for at least 2 years and very likely would retard the rate of so-called age-related functional decline in physical performance. Although further studies will likely quantify the potential benefits of exercise in preventing such adverse outcomes as falls and fractures, the evidence is suggestive enough that most practitioners will want to incorporate regular, supervised or unsupervised exercise as a general “health promotion” activity for older patients. Patients with frailty and muscle weakness sufficient to impair function or increase risk of falls and fractures will likely benefit from more vigorous strengthening programs such as those described by Fiatarone.11 More vigorous application of “prehab” to hospitalized older patients, that is, early and vigorous ambulation, muscle strengthening exercises, and prescription of home-based conditioning programs after hospitalization, may also reverse the so-called “natural” history of functional morbidity10 we see in so many elderly hospitalized patients. Ultimately, the main barrier to efforts to improve physical condition and function may flounder on the natural reluctance of patients (and to some extent, practitioners) to participate in preventive or health promotion activities. Exercise is well known to be one of the least practiced of all the health promoting activities.12 Physicians should play an active role in promoting exercise for their individual patients and could also play a leadership role promoting exercise at institutional and public levels and through the mass media. The medical benefits and functional gains possible from routine physical conditioning need to be communicated to the lay public. The as yet unrealized potential for vigorous therapeutic exercise to actually reverse frailty and functional impairment should be considered in the design of institutional programs for at-risk elders.