Bowen, TS, Koga, S, Amano, T et al. (2 more authors) (2016) The Spatial Distribution of Absolute Skeletal Muscle Deoxygenation During Ramp-Incremental Exercise Is Not Influenced by Hypoxia. In: Elwell, CE, Leung, TS and Harrison, DK, (eds.) Oxygen Transport to Tissue XXXVII. Advances in Experimental Medicine and Biology, 876 . Springer , New York, USA , pp. 19-26. ISBN 978-1-4939-3022-7
Abstract
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 (VO₂) 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). VO₂peak 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.
Metadata
Item Type: | Book Section |
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Authors/Creators: |
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Editors: |
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Copyright, Publisher and Additional Information: | © 2016 Springer Science+Business Media, New York. This is an author produced version of a paper published in Oxygen Transport to Tissue XXXVII (Advances in Experimental Medicine and Biology, 876). The final publication is available at Springer via https://doi.org/10.1007/978-1-4939-3023-4_2. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | HHb; Heterogeneity; NIRS; Near infrared-spectroscopy; Skeletal muscle |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 07 Dec 2016 11:35 |
Last Modified: | 12 Apr 2017 02:41 |
Published Version: | https://doi.org/10.1007/978-1-4939-3023-4_2 |
Status: | Published |
Publisher: | Springer |
Series Name: | Advances in Experimental Medicine and Biology |
Identification Number: | 10.1007/978-1-4939-3023-4_2 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:109165 |