Boushel 2015 Scand J Med Sci Sports

Boushel R, Gnaiger E, Larsen FJ, Helge JW, Gonzalez-Alonso J, Ara I, Munch-Andersen T, van Hall G, Søndergaard H, Saltin B, Calbet JAL (2015) Maintained peak leg and pulmonary VO2 despite substantial reduction in muscle mitochondrial capacity. Scand J Med Sci Sports 25 (Suppl 4):135–43.

» PMID: 26589127 Open Access

Boushel R, Gnaiger Erich, Larsen FJ, Helge JW, Gonzalez-Alonso J, Ara I, Munch-Andersen T, van Hall G, Soendergaard H, Saltin Bengt, Calbet Jose AL (2015) Scand J Med Sci Sports

Abstract: We recently reported the circulatory and muscle oxidative capacities of the arm after prolonged low-intensity skiing in the arctic (Boushel et al., 2014). In the present study, leg V_O2 was measured by the Fick method during leg cycling while muscle mitochondrial capacity was examined on a biopsy of the vastus lateralis in healthy volunteers (7 male, 2 female) before and after 42 days of skiing at 60% HR max. Peak pulmonary V_O2 (3.52 ± 0.18 L.min^-1 pre vs 3.52 ± 0.19 post) and V_O2 across the leg (2.8 ± 0.4 L.min^-1 pre vs 3.0 ± 0.2 post) were unchanged after the ski journey. Peak leg O₂ delivery (3.6 ± 0.2 L.min^-1 pre vs 3.8 ± 0.4 post), O₂ extraction (82 ± 1% pre vs 83 ± 1 post), and muscle capillaries per mm² (576 ± 17 pre vs 612 ± 28 post) were also unchanged; however, leg muscle mitochondrial OXPHOS capacity was reduced (90 ± 3 pmol.s^-1.mg^-1 pre vs 70 ± 2 post, P < 0.05) as was citrate synthase activity (40 ± 3 µmol.min^-1.g^-1 pre vs 34 ± 3; P < 0.05). These findings indicate that peak muscle V_O2 can be sustained with a substantial reduction in mitochondrial OXPHOS capacity. This is achieved at a similar O₂ delivery and a higher relative ADP-stimulated mitochondrial respiration at a higher mitochondrial p₅₀. These findings support the concept that muscle mitochondrial respiration is submaximal at V_O2max, and that mitochondrial volume can be downregulated by chronic energy demand.

• Bioblast editor: Gnaiger E • O2k-Network Lab: CA Vancouver Boushel RC, AT Innsbruck Gnaiger E, AT Innsbruck Oroboros, ES CN Las Palmas Calbet JAL, SE Stockholm Larsen FJ

Greenland expedition CMRC: science and adventure

» Greenland Expedition CMRC

Cited by

• 9 articles in PubMed (2021-12-27) https://pubmed.ncbi.nlm.nih.gov/26589127/

Labels: MiParea: Respiration, Exercise physiology;nutrition;life style 

Organism: Human  Tissue;cell: Skeletal muscle  Preparation: Intact organ, Permeabilized tissue 

Coupling state: OXPHOS  Pathway: F, N, S, NS  HRR: Oxygraph-2k 

MitoFitPublication, VO2max