title: Maximal oxygen uptake is proportional to muscle fiber oxidative capacity, from chronic heart failure patients to professional cyclists.
abstract: V̇o2 max during whole body exercise is presumably constrained by oxygen delivery to mitochondria rather than by mitochondria's ability to consume oxygen. Humans and animals have been reported to exploit only 60-80% of their mitochondrial oxidative capacity at maximal oxygen uptake (V̇o2 max). However, ex vivo quantification of mitochondrial overcapacity is complicated by isolation or permeabilization procedures. An alternative method for estimating mitochondrial oxidative capacity is via enzyme histochemical quantification of succinate dehydrogenase (SDH) activity. We determined to what extent V̇o2 max attained during cycling exercise differs from mitochondrial oxidative capacity predicted from SDH activity of vastus lateralis muscle in chronic heart failure patients, healthy controls, and cyclists. V̇o2 max was assessed in 20 healthy subjects and 28 cyclists, and SDH activity was determined from biopsy cryosections of vastus lateralis using quantitative histochemistry. Similar data from our laboratory of 14 chronic heart failure patients and 6 controls were included. Mitochondrial oxidative capacity was predicted from SDH activity using estimated skeletal muscle mass and the relationship between ex vivo fiber V̇o2 max and SDH activity of isolated single muscle fibers and myocardial trabecula under hyperoxic conditions. Mitochondrial oxidative capacity predicted from SDH activity was related (r(2) = 0.89, P < 0.001) to V̇o2 max measured during cycling in subjects with V̇o2 max ranging from 9.8 to 79.0 ml·kg(-1)·min(-1) V̇o2 max measured during cycling was on average 90 ± 14% of mitochondrial oxidative capacity. We conclude that human V̇o2 max is related to mitochondrial oxidative capacity predicted from skeletal muscle SDH activity. Mitochondrial oxidative capacity is likely marginally limited by oxygen supply to mitochondria.
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands; s.vander.zwaard@vu.nl.
authors.forename: Stephan
authors.identifier: 0000-0002-8296-828X
authors.initials: S
authors.lastname: van der Zwaard
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands;
authors.forename: C Jo
authors.initials: CJ
authors.lastname: de Ruiter
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands;
authors.forename: Dionne A
authors.initials: DA
authors.lastname: Noordhof
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands;
authors.forename: Renske
authors.initials: R
authors.lastname: Sterrenburg
authors.affiliation: Department of Trauma Surgery, VU University Medical Center Amsterdam, Amsterdam, The Netherlands;
authors.forename: Frank W
authors.initials: FW
authors.lastname: Bloemers
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands;
authors.forename: Jos J
authors.initials: JJ
authors.lastname: de Koning
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands; Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands; and.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Jaspers
authors.affiliation: Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Willem J
authors.initials: WJ
authors.lastname: van der Laarse
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D002908:Chronic Disease; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008931:Mitochondria, Muscle / Q000502:physiology*; D008954:Models, Biological; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*
chemical_list: D010100:Oxygen
keywords: V̇o2 max; mitochondria; oxygen supply; succinate dehydrogenase; symmorphosis