Aging, exercise, and muscle protein metabolism

Abstract

Koopman R, van Loon LJ. Aging, exercise, and muscle protein metabolism. J Appl Physiol 106: 2040 -2048. First published January 8, 2009 doi:10.1152/japplphysiol.91551.2008Aging is accompanied by a progressive loss of skeletal muscle mass and strength, leading to the loss of functional capacity and an increased risk of developing chronic metabolic disease. The age-related loss of skeletal muscle mass is attributed to a disruption in the regulation of skeletal muscle protein turnover, resulting in an imbalance between muscle protein synthesis and degradation. As basal (fasting) muscle protein synthesis rates do not seem to differ substantially between the young and elderly, many research groups have started to focus on the muscle protein synthetic response to the main anabolic stimuli, i.e., food intake and physical activity. Recent studies suggest that the muscle protein synthetic response to food intake is blunted in the elderly. The latter is now believed to represent a key factor responsible for the age-related decline in skeletal muscle mass. Physical activity and/or exercise stimulate postexercise muscle protein accretion in both the young and elderly. However, the latter largely depends on the timed administration of amino acids and/or protein before, during, and/or after exercise. Prolonged resistance type exercise training represents an effective therapeutic strategy to augment skeletal muscle mass and improve functional performance in the elderly. The latter shows that the ability of the muscle protein synthetic machinery to respond to anabolic stimuli is preserved up to very old age. Research is warranted to elucidate the interaction between nutrition, exercise, and the skeletal muscle adaptive response. The latter is needed to define more effective strategies that will maximize the therapeutic benefits of lifestyle intervention in the elderly. sarcopenia; nutrition; exercise training; muscle hypertrophy AT PRESENT, MANY DISCUSSIONS focus on the public health implications of global aging. The latter should not be a surprise, as demographics show that the world's population aged 60 yr and over will triple within 50 yr, from 600 million in the year 2000 to more than 2 billion by 2050. Two-thirds of the elderly people are presently living in the developed world, and this will continue to rise up to 75%. Due to greater longevity, the subpopulation of elderly people aged 80 yr and over is presently the fastest growing subpopulation in the developed world (130). This global aging will have a major impact on our healthcare system due to increased morbidity and greater need for hospitalization and/or institutionalization. Good health is essential for older people to remain independent and to continue to actively take part in family and community life. Life-long health promotion is warranted to prevent or delay the onset of noncommunicable and chronic metabolic diseases, like heart disease, stroke, cancer, and diabetes.One of the factors that plays an important role in the loss of functional performance and, as...

The Role of Mechanical Loading in Tendon Development, Maintenance, Injury, and Repair

“…Disuse muscle atrophy and weakness are causes of impaired function in older individuals [74][75][76][77][78] . While age-related sarcopenia has been repeatedly documented, the effect of aging on tendon biomechanical properties is inconclusive 74,[79][80][81][82][83] .…”

“…While age-related sarcopenia has been repeatedly documented, the effect of aging on tendon biomechanical properties is inconclusive 74,[79][80][81][82][83] . Methodological differences make study comparisons difficult, although the majority of investigators have suggested that collagen loss occurs in older individuals [84][85][86] .…”

Elevated SOCS3 and altered IL-6 signaling is associated with age-related human muscle stem cell dysfunction

“…The normal aging process has a profound effect on the structure and function of skeletal muscle. Aged muscle undergoes progressive atrophy, with a decrease in cross-sectional area caused by a decrease in muscle fiber number and fiber size (24,29). Muscle function also appears to be reduced in aged muscle, displaying a decrease in power and maximum force production (6).…”

Ameliorating Effects of Sphingomyelin-Based Liposomes on Sarcopenia in Senescence-Accelerated Mice

“…Although the biochemical and molecular mechanisms responsible for the loss of muscle during aging are not fully understood, 2,3) the loss of muscle during aging is known to be the result of both decreased protein synthesis and increased protein degradation. 34,35) Currently, protection against or prevention of sarcopenia is exercise and eating proper nutrition. Exercise, specifically resistance training or strength training, increases muscle strength and endurance.…”