The Spatial Distribution of Absolute Skeletal Muscle Deoxygenation During Ramp-Incremental Exercise Is Not Influenced by Hypoxia

  • T. Scott BowenEmail author
  • Shunsaku Koga
  • Tatsuro Amano
  • Narihiko Kondo
  • Harry B. Rossiter
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 876)


Time-resolved near-infrared spectroscopy (TRS-NIRS) allows absolute quantitation of deoxygenated haemoglobin and myoglobin concentration ([HHb]) in skeletal muscle. We recently showed that the spatial distribution of peak [HHb] within the quadriceps during moderate-intensity cycling is reduced with progressive hypoxia and this is associated with impaired aerobic energy provision. We therefore aimed to determine whether reduced spatial distribution of skeletal muscle [HHb] was associated with impaired aerobic energy transfer during exhaustive ramp-incremental exercise in hypoxia. Seven healthy men performed ramp-incremental cycle exercise (20 W/min) to exhaustion at 3 fractional inspired O2 concentrations (FIO2): 0.21, 0.16, 0.12. Pulmonary O2 uptake (\( \dot{\mathrm{V}}{\mathrm{O}}_2 \)) was measured using a flow meter and gas analyser system. Lactate threshold (LT) was estimated non-invasively. Absolute muscle deoxygenation was quantified by multichannel TRS-NIRS from the rectus femoris and vastus lateralis (proximal and distal regions). \( {{\dot{\mathrm{V}}\mathrm{O}}_2}_{\mathrm{peak}} \) and LT were progressively reduced (p < 0.05) with hypoxia. There was a significant effect (p < 0.05) of FIO2 on [HHb] at baseline, LT, and peak. However the spatial variance of [HHb] was not different between FIO2 conditions. Peak total Hb ([Hbtot]) was significantly reduced between FIO2 conditions (p < 0.001). There was no association between reductions in the spatial distribution of skeletal muscle [HHb] and indices of aerobic energy transfer during ramp-incremental exercise in hypoxia. While regional [HHb] quantified by TRS-NIRS at exhaustion was greater in hypoxia, the spatial distribution of [HHb] was unaffected. Interestingly, peak [Hbtot] was reduced at the tolerable limit in hypoxia implying a vasodilatory reserve may exist in conditions with reduced FIO2.


Heterogeneity HHb Near infrared-spectroscopy NIRS Skeletal muscle 



Support provided by the Medical Research Council UK (studentship to TSB), BBSRC UK (BB/1024798/1; BB/I00162X/1), and The Japan Society for the Promotion of Science, the Ministry of Education, Science, and Culture of Japan (Grant-in-Aid: 22650151 to SK). TSB is a Postdoctoral Research Fellow of the Alexander von Humboldt Foundation.


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Copyright information

© Springer Science+Business Media, New York 2016

Authors and Affiliations

  • T. Scott Bowen
    • 1
    Email author
  • Shunsaku Koga
    • 2
  • Tatsuro Amano
    • 3
  • Narihiko Kondo
    • 3
  • Harry B. Rossiter
    • 4
    • 5
  1. 1.Department of Internal Medicine and CardiologyLeipzig University, Heart CenterLeipzigGermany
  2. 2.Applied Physiology LaboratoryKobe Design UniversityKobeJapan
  3. 3.Graduate School of Human Development and Environment, Laboratory for Applied Human PhysiologyKobe UniversityKobeJapan
  4. 4.Division of Respiratory and Critical Care Physiology and MedicineRehabilitation Clinical Trials Center, Los Angeles Biomedical Research Institute and Harbor-UCLA Medical CenterTorranceUSA
  5. 5.School of Biomedical SciencesUniversity of LeedsLeedsUK

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