Changes in skeletal muscle with aging: effects of exercise training

Area of Science:

• Gerontology
• Skeletal Muscle Physiology
• Exercise Science

Background:

• Aging is associated with a substantial decline in muscle strength (approx. 30%) and muscle area (approx. 40%) between the second and seventh decades of life.
• This age-related muscle loss is attributed to a decrease in both Type I and Type II muscle fiber numbers and size, with Type II fibers experiencing preferential atrophy.
• While glycolytic capacity remains unchanged, senescent skeletal muscle shows a ~25% reduction in oxidative enzyme activity and capillarization.

Purpose of the Study:

• To investigate the impact of exercise training on age-related skeletal muscle decline.
• To determine if older individuals can adapt to exercise training similarly to younger populations.
• To explore the potential of exercise to mitigate sarcopenia and improve health outcomes in aging.

Main Methods:

• Review of studies involving endurance exercise training in older adults, focusing on progressive increases in stimulus.
• Analysis of studies on progressive resistance training in older individuals, examining intensity and duration effects.
• Comparison of adaptive responses to exercise in older versus younger populations.

Main Results:

• Vigorous endurance exercise training in older adults stimulated muscle capillary proliferation, enhanced oxidative enzyme activity, and significantly improved maximal oxygen consumption (VO2max).
• Progressive resistance training in older individuals led to muscle hypertrophy and increased strength, provided sufficient training intensity and duration were applied.
• Older individuals demonstrated adaptive capabilities to both endurance and resistive exercise training comparable to those seen in younger individuals.

Conclusions:

• The decline in muscle metabolic and force-producing capacity is not an inevitable consequence of aging.
• Exercise training adaptations in aging skeletal muscle can effectively prevent sarcopenia.
• Exercise interventions can enhance daily living activities and positively impact age-associated diseases like Type II diabetes, coronary artery disease, hypertension, osteoporosis, and obesity.