Frailty in the elderly: the physical dimension.

Frailty may be considered as a vulnerable status, which can precede the onset of overt disability. Operational definitions of frailty vary widely according to the conceptual framework: some authors consider frailty in a broad sense, which encompasses the physical, social, cognitive, psychological dimensions and comorbidity, whereas others define the syndrome more restrictively, mainly on the basis of performance parameters, such as gait speed, grip strength and physical activity. All these definitions are provided of a high predictive value for adverse outcomes, such as disability, hospitalization and mortality. Sarcopenia (i.e. the reduction of muscular mass and function) plays a predominant role in the pathogenesis of frailty. Among the factors responsible for sarcopenia (such as proinflammatory cytokines, low growth hormone and testosterone levels, increased production of oxygen free radicals, malnutrition and reduced neurological drive), immobility and lack of exercise have a preponderant role. Therefore, the diagnosis of frailty is mandatory for the early identification of a subset of elderly subjects at high risk, which can receive benefit from rehabilitation. A self-report and objective evaluation of physical performance are the best indicators of frailty in elderly subjects, a poor performance suggesting the need of an early and proper intervention. Structured exercise programs are effective in contrasting the progression of frailty, but an healthy and active lifestyle may be sufficient for delaying the onset of disability. In conclusion, there is clear evidence for prescription of exercise within the mainstream of the medical practice, rather than as an optional adjunct to standard care of the oldest old, given the public health implication of frailty, whose prevalence is going to increase in western populations.