Declining fitness (˙VO2 peak) is a hallmark of ageing and believed to arise from decreased oxygen delivery and reduced muscle oxidative capacity. Physical activity is a modifiable lifestyle factor that is critical when evaluating the effects of age on parameters of fitness and energy metabolism. The objective was to evaluate the effects of age and sex on ˙VO2peak,muscle mitochondrial physiology, and physical activity in young and older adults. An additional objective was to assess the contribution of skeletal muscle oxidative capacity to age-related reductions in ˙VO2peak and determine if age-related variation in ˙VO2peak and muscle oxidative capacity could be explained on the basis of physical activity levels. In 23 young and 52 older men and women measurements were made of ˙V O2peak, mitochondrial physiology in permeabilized muscle fibres, and free-living physical activity by accelerometry. Regression analyses were used to evaluate associations between age and ˙VO2peak, mitochondrial function, and physical activity. Significant age-related reductions were observed for ˙V O2peak (P < 0.001), but not muscle mitochondrial capacity. Total daily step counts did not decrease with age, but older adults showed lower moderate-to-vigorous physical activity,which was associated with ˙VO2peak (R2 = 0.323, P < 0.001) and muscle oxidative capacity (R2 = 0.086, P = 0.011).

Creator

• Gries, Kevin

• Zhang, X.

• Polley, E.C.

• Hart, C.R.

• Kunz, H.E.

• Lanza, I.R.

Publisher

• The Physiological Society

Language

• English

Identifier

• PMID: 34032280

• DOI:10.1113/JP281691

Stichwort

• skeletal muscle

• mitochondria

• physical activity

• ageing

Date created

• 2021

Related URL

• Available from Pubmed:  https://pubmed.ncbi.nlm.nih.gov/34032280/

• Available from the publisher website: https://doi.org/10.1113/JP281691

• Available for access or request from the library catalog: Preserved skeletal muscle oxidative capacity in older adults despite decreased cardiorespiratory fitness with ageing

Resource type

• Article

Source

• The Journal of Physiology, 2021: 599.14

Rights statement

• http://rightsstatements.org/vocab/InC/1.0/