Interventions for Human Frailty: Physical Activity as a Model

Abstract

In the last 100 years, populations in developed countries have experienced an unprecedented addition of 30 years to life expectancy. Developing countries are now experiencing this same phenomenon, but over a shorter time frame. With this success comes the challenge of maximizing health and vitality across these added years. The compression of morbidity to the latest point in the human life span could unleash a sustained third demographic dividend that benefits all of society. To accomplish this, society needs to invest in the prevention and treatment of frailty, as well as in the prevention of chronic diseases at every age and stage of life. A model intervention, physical activity, may offer a road map.

Figure 1.

Age emerges as an independent predictor of mortality, independent of chronic diseases, beginning at age 85 years, based on analyses in community-dwelling men and women 65 years and older in four U.S. communities participating in the Cardiovascular Health Study. (From Fried et al. 1998; reprinted, with permission.)

Figure 2.

Vicious cycle of frailty in older adults. An expression of dysregulated energetics, evidence indicates that numerous exposures and chronic diseases, as well as aging-related processes, can initiate this cycle at any point. However, the early manifestations in the main are declines in muscle strength, walking speed, and/or physical activity, which predict development of exhaustion and—at end stages—significant unintentional weight loss. (From Fried et al. 2001; reprinted with permission.)

Figure 3.

Association of number of physiological systems at abnormal levels with prevalence of being frail, women aged 70–79 (p < 0.01 for quantitative trend). (From Fried et al. 2009; reprinted, with permission.)

Figure 4.

Physical activity positively affects function of multiple components of the syndrome of frailty at levels of (A) frailty phenotype, (B) physiologic dysregulation, and (C) cellular function. DHEA-S, didehydroepiandrosterone sulfate; GH, growth hormone; HPA, hypothalamic–pituitary–adrenal; SNS, sympathetic nervous system.