Exercise efficiency relates with mitochondrial content and function in older adults

Physiological Reports

Nicholas T. Broskey⁴  Andreas Boss²  Elie-Jacques Fares⁴  Chiara Greggio⁴  Gerald Gremion³  Leo Schlüter¹  Didier Hans⁵  Roland Kreis²  Chris Boesch² 

[1] Service of Cardiology, University Hospital, Lausanne, Switzerland;Department of Clinical Research & Institute of Interventional, Diagnostic and Pediatric Radiology, University of Bern, Bern, Switzerland;Sports Medicine Unit, University Hospital, Lausanne, Switzerland;Department of Physiology, School of Biology and Medicine, University of Lausanne, Lausanne, Switzerland;Center for Bone Disease, Bone & Joint Department, University Hospital, Lausanne, Switzerland

关键词: Chronic exercise;    delta efficiency;    gross efficiency;    net efficiency;   

DOI  :  10.14814/phy2.12418

来源: Wiley

【 摘 要 】

Abstract

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˙O_2peak 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˙O_2peak). Delta efficiency (DE, %) was calculated from the GXT. Mitochondrial function was measured as ATP_max (mmol/L/s) during a PCr recovery protocol with ³¹P-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 ATP_max was 24% higher in A than in S. All efficiencies positively correlated with both ATP_max 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.

【 授权许可】

CC BY   
© 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.