Muscle phosphocreatine post-exercise recovery rate is related to functional evaluation in hospitalized and community-living older people

Abstract

Objective: to explore muscle mitochondria function with respect to age, functional status and nutrition in community-living and recovering hospitalized older subjects.

Measurements: subjects were assessed for nutrition, hand-grip strength, 10-meter gait time, a modified timed get-up-and-go test and activities of daily living score (ADL). 31P magnetic resonance spectroscopy (31P MRS) was used to assess the initial rate of post-exercise phosphocreatine recovery (ViPCr) for mitochondrial function evaluation in 25 hospitalized older subjects (86.1 + 5.3 y) and in 25 community-living younger ones (74.5 + 6.2 y).

Results: in multiple linear regression, longer time on the get-up-and-go test was independently associated with lower values of ViPCr (p = 0.008). For all subjects and in the 8 patients unable to perform this test, ViPCr was negatively correlated with the ADL score (respectively p < 0.001 and p = 0.025).

Conclusion: particularly in hospitalized and frail older subjects, muscle mitochondrial function was related to the global physical functional assessment.