Phillips, Bethan E., Williams, John P., Greenhaff, Paul L., Smith, Kenneth and Atherton, Philip J.
(2017)
Physiological adaptations to resistance exercise as a function of age.
JCI Insight, 2
(17).
ISSN 2379-3708
Full text not available from this repository.
Abstract
BACKGROUND. The impact of resistance exercise training (RE-T) across the life span is poorly defined.
METHODS. To resolve this, we recruited three distinct age cohorts of young (18–28 years; n = 11), middle-aged (45–55 years; n = 20), and older (nonsarcopenic; 65–75 years; n = 17) individuals to a cross-sectional intervention study. All subjects participated in 20 weeks of fully supervised whole-body progressive RE-T, undergoing assessment of body composition, muscle and vascular function, and metabolic health biomarkers before and after RE-T. Individuals also received stable isotope tracer infusions to ascertain muscle protein synthesis (MPS).
RESULTS. There was an age-related increase in adiposity, but only young and middle-age groups demonstrated reductions following RE-T. Increases in blood pressure with age were attenuated by RE-T in middle-aged, but not older, individuals, while age-related increases in leg vascular conductance were unaffected by RE-T. The index of insulin sensitivity was reduced by RE-T in older age. Despite being matched at baseline, only younger individuals increased muscle mass in response to RE-T, and there existed a negative correlation between age and muscle growth; in contrast, increases in mechanical quality were preserved across ages. Acute increases in MPS (upon feeding plus acute RE-T) were enhanced only in younger individuals, perhaps explaining greater hypertrophy.
CONCLUSION. Our data indicate that RE-T offsets some, but not all, negative characteristics of ageing — some of which are apparent in midlife.
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