Sarcopenia

While both cardiopulmonary fitness and muscle strength are important determinants of functional capacity; in frail, elderly persons with advanced sarcopenia, muscle weakness may be more limiting than aerobic fitness. Weakness in turn leads to further disuse, as people avoid activities that are uncomfortable. Thus, reduced physical activity follows loss of muscle mass, and then accelerates it by removing the trophic stimulus of the activity. The improved survival and reduced disability of elderly athletes who remain physically active suggest that such a vicious cycle is avoidable under some circumstances. More importantly, perhaps, the ability to reverse these changes with progressive resistance training (PRT) suggests that they are modifiable effects of aging.

Many studies have now documented that exercise training can reverse sarcopenia, and that people who retain a high level of physical activity throughout their lives maintain a higher level of physical functioning and live longer. In addition, physical activity is one of the few factors that are within the control of nearly everyone, and it does not require pharmacological treatment. Moreover, Fiatarone, et al. have shown that it is never too late to begin strength training, and that even frail, elderly, nursing home patients in their nineties retain the plasticity of muscle in response to training. The effectiveness of strength training is clear, and the effect can be obtained in as little as eight weeks with training two to three times per week. Strength training can be done with low-tech, relatively low-cost equipment in the home, or in congregate settings such as gyms or senior centers. In addition, strength training can be used safely in people with arthritis, coronary artery disease, heart failure, and renal failure. The difficulty with strength training is translating it into an effective public health intervention on a large scale. This requires training an adequate number of exercise leaders who can, in turn, train others. This is a serious impediment to application of this therapy.