Exercise efficiency relates with mitochondrial content and function in older adults

Broskey, Nicholas T; Boss, Andreas; Fares, Elie-Jacques; Greggio, Chiara; Gremion, Gerald; Schlüter, Leo; Hans, Didier; Kreis, Roland; Boesch, Christoph Hans; Amati, Francesca (2015). Exercise efficiency relates with mitochondrial content and function in older adults. Physiological reports, 3(6), e12418. The American Physiological Society 10.14814/phy2.12418

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Chronic aerobic exercise has been shown to increase exercise efficiency, thus allowing less energy expenditure for a similar amount of work. The extent to which skeletal muscle mitochondria play a role in this is not fully understood, particularly in an elderly population. The purpose of this study was to determine the relationship of exercise efficiency with mitochondrial content and function. We hypothesized that the greater the mitochondrial content and/or function, the greater would be the efficiencies. Thirty-eight sedentary (S, n = 23, 10F/13M) or athletic (A, n = 15, 6F/9M) older adults (66.8 ± 0.8 years) participated in this cross sectional study. V˙O2peak was measured with a cycle ergometer graded exercise protocol (GXT). Gross efficiency (GE, %) and net efficiency (NE, %) were estimated during a 1-h submaximal test (55% V˙O2peak). Delta efficiency (DE, %) was calculated from the GXT. Mitochondrial function was measured as ATPmax (mmol/L/s) during a PCr recovery protocol with (31)P-MR spectroscopy. Muscle biopsies were acquired for determination of mitochondrial volume density (MitoVd, %). Efficiencies were 17% (GE), 14% (NE), and 16% (DE) higher in A than S. MitoVD was 29% higher in A and ATPmax was 24% higher in A than in S. All efficiencies positively correlated with both ATPmax and MitoVd. Chronically trained older individuals had greater mitochondrial content and function, as well as greater exercise efficiencies. GE, NE, and DE were related to both mitochondrial content and function. This suggests a possible role of mitochondria in improving exercise efficiency in elderly athletic populations and allowing conservation of energy at moderate workloads.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic, Interventional and Paediatric Radiology > DCR Magnetic Resonance Spectroscopy and Methodology (AMSM)

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Boss, Andreas; Kreis, Roland and Boesch, Christoph Hans

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

2051-817X

Publisher:

The American Physiological Society

Language:

English

Submitter:

Christoph Hans Boesch

Date Deposited:

29 Jun 2015 16:36

Last Modified:

19 Apr 2016 12:38

Publisher DOI:

10.14814/phy2.12418

PubMed ID:

26059033

Uncontrolled Keywords:

Chronic exercise, delta efficiency, gross efficiency, net efficiency

BORIS DOI:

10.7892/boris.69837

URI:

https://boris.unibe.ch/id/eprint/69837

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