Open AccessExercise efficiency relates with mitochondrial content and function in older adults
Author(s) -
Broskey Nicholas T.,
Boss Andreas,
Fares ElieJacques,
Greggio Chiara,
Gremion Gerald,
Schlüter Leo,
Hans Didier,
Kreis Roland,
Boesch Chris,
Amati Francesca
Publication year - 2015
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12418
Subject(s) - cycle ergometer , skeletal muscle , mitochondrion , medicine , population , aerobic exercise , endocrinology , cardiology , physical therapy , biology , biochemistry , heart rate , environmental health , blood pressure
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 PC r 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. Mito VD 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.