Muscle Capillarization and Sarcopenia

Increasing Muscle Capillarization to Enhance Responses to Strength Training in Sarcopenia

Aging is associated with a loss of muscle mass, termed sarcopenia, that reduces mobility, decreases physical function and accelerates progression of other age-related disorders. This study is designed to determine whether increasing skeletal muscle capillarization through aerobic exercise will enhance muscular adaptations to strength training in older adults with sarcopenia.

Sarcopenia, or the aging-related loss of muscle mass, affects a large number of older adults. The presence of sarcopenia is associated with physical disability, poor quality of life, and all-cause mortality, in part because sarcopenic adults have low muscle skeletal muscle capillarization and may lack the adequate perfusion needed to maintain muscle mass and function. This study will test the effects of increasing skeletal muscle capillarization through aerobic exercise training on responses to resistance training in older adults. Eligible participants will be randomized to one of two groups, resistance training preceded by aerobic exercise training (AEX-RT), or resistance training followed by aerobic exercise training (RT-AEX). Participants in the AEX-RT group will undergo 3 months of aerobic exercise training to increase skeletal muscle capillarization, followed by 3 months of resistance training. Participants in the RT-AEX group will undergo 3 months of resistance training, followed by 3 months of aerobic exercise training. Before and after the interventions, participants will undergo assessments of muscle size, strength, and capillarization, as well as assessments of physical function.

Inclusion Criteria:

• Body Mass Index = 18-32.5 kg/m2
• Non-smoker
• Presence of at least moderate sarcopenia (low muscle mass per unit body height)

Exclusion Criteria:

• Diagnosis of diabetes, cancer, pulmonary or renal disease
• Physical impairment preventing exercise
• Recent history of exercise training