High Intensity Strength Training in Nonagenarians
Maria A. Fiatarone Singh, M.D., Boston
Over the past 10 years we have pioneered the use of high intensity progressive resistance training in frail elders between 80 and 105 years of age. The concept of using this mode of exercise in such an aged population was generated by the realization that sarcopenia and its associated muscle dysfunction and metabolic consequences is a major impediment to attainment of the fullest possible quality of life in this cohort. While most individuals in the ninth and tenth decades of life have survived or not suffered major cardiovascular events, and most chronic diseases they will experience have already expressed themselves by this time, their health status may be markedly influenced by syndromes for which general medical care has had little ability to prevent or treat, including mobility impairment, gait and balance disorders, weakness, functional decline, falls, depression, insomnia, anorexia and wasting.
Loss of muscle tissue (sarcopenia) increases the risk for weakness, functional decline, impaired gait, falls, infections, glucose iontolerance, and osteoporotic fracture, among other things, and is therefšre a prime target for intervention in this age group. Potential mediators of sacropenia include biologic aging of the neuromuscular system, malnutrition, physical inactivity, withdrawal of anabolic hormonal influences, and catabolic diseases and medications. It is known that progressive resistance training may lead to muscle hypertrophy, whereas cardiovascular endurance training does not in general improve either muscle strength or mass. Therefšre, it makes sense to direct the exercise prescription in this way to target sarcopenia. In addition, multiple physical impairments and ambulatory difficulties as well as cardiovascular disease often make the prescription of endurance training difficult or impossible in this population, whereas seated resistive exercises can be applied to a much broader range of individuals.
We have seen that high intensity progressive resistance training is feasible, safe, and effective in nonagenarians in a variety of settings: nursing home, chronic hospital, outpatient clinics, continuing care communities, and individual homes. The injury rate is extremely low, and very few medical conditions are incompatible with its usage. It can be administered by individuals themselves, family, caregivers, students and volunteers after simple training courses. The benefits we have seen to date include improvements in muslcle strength, muscle mass, gait speed, balance, stairclimbing ability, overall physical activity levels, functional status, morale, depression, sleep, and nutritional intake. Muscle biopsy samples indicate activation of satellite cells and myogenic precursor appearance, as well as expression of developmental myosin and IGF-1, all indicative of the plasticity and remodeling of the skeletal muscle at this very advanced age. Current studies are exploring the benefits of vahous combinations of strength, power, balance, and endurance training in this group, as well as the specific effects of resistance training on patients with congestive heart failure, chronic renal failure, osteoarthritis, and Type 2 diabetes.