Current Aging Science - Volume 4, Issue 3, 2011

Demographers expect the number of older persons to double to 86.7 million— or to 20.6% of the US population— by the year 2050. As has occurred over the past decade, the health care costs associated with older age are expected to steadily increase approximately 2% per year causing both a public health and personal burden. A key component to reducing health care costs and maintaining well-being in older pe Read More

Aging is associated with dramatic reductions in muscle strength and motor control, and many of these agerelated changes in muscle function result from adaptations in the central nervous system. Aging is associated with widespread qualitative and quantitative changes of the motor cortex. For example, advancing age has been suggested to result in cortical atrophy, reduced cortical excitability, reduced cortical plasticity, as well Read More

Alterations in motor unit behavior associated with aging deteriorate fine or gross motor performance. In human aging, the alterations depend on muscles and the habitual activity of each muscle. This paper will discuss the current knowledge on the adaptations in major aspects of motor unit behavior including recruitment order, mean and maximal discharge rate, synchronized discharges, oscillatory discharges, and discharge Read More

The neuromuscular system is one of the largest and most vital organ systems of the body. The function and mass of the neuromuscular system gradually deteriorate during the natural process of aging. The neuromuscular system is comprised of individual motor units, each of which features a single motor neuron and all the muscle fibers it innervates. Motor units also demonstrate age-related remodeling such as reduced nu Read More

Skeletal muscle undergoes numerous morphological changes from early adulthood to old age including muscle size, configuration, and structure. This review discusses these changes, considers the limitations in interpreting studies, addresses the potential health implications, and describes some mechanisms and interventions to ameliorate aging-related changes in skeletal muscle. Discussion in each section focuses on mea Read More

Properly functioning skeletal muscle is critical for locomotion and performance of many activities of daily living. Muscle wasting and decreased function of skeletal muscle are important factors in many age-related morbidities. There are several pathways for generating ATP in skeletal muscle that allow adequate ATP supply to meet increased demand during muscle activity. A growing body of literature provides evidenc Read More

Functional and structural decline of the neuromuscular system is a recognized cause of decreased strength, impaired performance of daily living activities, and loss of independence in the elderly. However, in mammals, including humans, age-related loss of strength is greater than loss of muscle mass, so the underlying mechanisms remain only partially understood. This review focuses on the mechanisms underlying impai Read More

The loss of lean muscle mass occurring with advancing age is termed sarcopenia. This condition often leads to a concomitant loss of strength, increased frailty and risk of falls and an overall loss of functional independence in the elderly. Muscle protein metabolism is a dynamic process characterized by the balance between the synthesis and breakdown of muscle proteins. A disturbance of this equilibrium can lead to the Read More

Age-related muscle atrophy is due to loss of muscle fibers as well as atrophy of the remaining fibers. Evidence shows that loss of myofibers may be, in part, due to apoptosis. Two major apoptotic pathways have been extensively studied which are the mitochondrion-mediated and receptor-mediated pathways. However, other pathways exist, such as the p53 pathway. To date, it is not completely clear what pathways are resp Read More

Vertebrate skeletal muscle fibers have two traits that make them unique: the fibers are multinucleated and their nuclei are post-mitotic. The activity and mass of the muscles in the body make them susceptible to constant injury. When this occurs, myonuclei can be increased or replaced by the adult stem cells of muscle, satellite cells (SCs). These SCs are vital for normal growth, repair and regeneration. This review collates rece Read More

Age related muscle loss, known as sarcopenia, is a major factor in disability, loss of mobility and quality of life in the elderly. There are many proposed mechanisms of age-related muscle loss that include the endocrine system. A variety of hormones regulate growth, development and metabolism throughout the lifespan. Hormone activity may change with age as a result of reduced hormone secretion or decreased tiss Read More