Aging and muscle disuse-induced functional declinephysiological mechanisms and preventive strategies

Abstract

Societies are progressively aging, and those aged >80 years represent the most rapidly expanding population segment. However, this process is associated with an increased incidence of the so-called ‘age-related conditions’, including a greater risk of functional decline that is further exacerbated during some situations such as hospitalization or in patients with chronic diseases. How to counteract aging-induced functional decline is therefore a major challenge for modern medicine. Under this context, the present project aimed to explore the physiological mechanisms underlying aging- and disuse-induced functional decline, as well as to analyze the role of physical exercise as a preventive strategy. Through a compendium of narrative reviews, clinical trials and systematic reviews with meta-analysis, the present project shows how lifelong exercise can attenuate the functional decline commonly observed with aging. Moreover, the benefits of inhospital physical exercise – or the application of exercise mimetics such as neuromuscular electrical stimulation when voluntary exercise is not feasible – in older adults at risk of functional decline such as those hospitalized with an acute medical condition or those who suffer from a chronic disease such as end-stage renal disease are also proven. Although further research is needed to determine the optimal exercise dose attending to the individual patients’ characteristic to maximize responsiveness, the present findings highlight the effectiveness of physical exercise in preventing aginginduced functional decline and support its routine implementation in daily life and particularly during disuse situations.