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Cited by 647Cardiovascular and exercise physiologyHemoglobin structure and functionHigh Altitude and Hypoxia

Myoglobin O2 desaturation during exercise. Evidence of limited O2 transport.

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Richardson, R S, Noyszewski, E A, Kendrick, K F, Leigh, J S, Wagner, P D·1995·Journal of Clinical Investigation
DOI 10.1172/jci118237PMC PMC185828
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Abstract

The assumption that cellular oxygen pressure (PO2) is close to zero in maximally exercising muscle is essential for the hypothesis that O2 transport between blood and mitochondria has a finite conductance that determines maximum O2 consumption. The unique combination of isolated human quadriceps exercise, direct measures of arterial, femoral venous PO2, and 1H nuclear magnetic resonance spectroscopy to detect myoglobin desaturation enabled this assumption to be tested in six trained men while breathing room air (normoxic, N) and 12% O2 (hypoxic, H). Within 20 s of exercise onset partial myoglobin desaturation was evident even at 50% of maximum O2 consumption, was significantly greater in H than N, and was then constant at an average of 51 +/- 3% (N) and 60 +/- 3% (H) throughout the incremental exercise protocol to maximum work rate. Assuming a myoglobin PO2 where 50% of myoglobin binding sites are bound with O2 of 3.2 mmHg, myoglobin-associated PO2 averaged 3.1 +/- .3 (N) and 2.1 +/- .2 mmHg (H). At maximal exercise, measurements of arterial PO2 (115 +/- 4 [N] and 46 +/- 1 mmHg [H]) and femoral venous PO2 (22 +/- 1.6 [N] and 17 +/- 1.3 mmHg [H]) resulted in calculated mean capillary PO2 values of 38 +/- 2 (N) and 30 +/- 2 mmHg(H). Thus, for the first time, large differences in PO2 between blood and intracellular tissue have been demonstrated in intact normal human muscle and are found over a wide range of exercise intensities. These data are consistent with an O2 diffusion limitation across the 1-5-microns path-length from red cell to the sarcolemma that plays a role in determining maximal muscle O2 uptake in normal humans.

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  • Conditions of low partial pressure oxygen and pH may exist in skeletal muscle during exercise.

    “Interestingly, these conditions (low partial pressure oxygen and pH) may exist in skeletal muscle during exercise [18].”

    From Dietary Nitrate Supplementation and Exercise Performance (2014) · cites this paper as [18]

  • Tissue hypoxia during submaximal exercise favors nitrite reduction to NO, providing an alternative NO source for vascular dilation and efficient O2 consumption in working muscles.

    “Because the nitrite-reducing factors are rich in skeletal muscles, tissue hypoxia during submaximal exercise kinetically favors nitrite reduction to NO, thus providing an alternative NO source for vascular dilation and efficient O2 consumption in the working muscles [35,36].”

    From NO-Rich Diet for Lifestyle-Related Diseases (2015) · cites this paper as [35]

  • The reduction of NO2− to NO is potentiated under conditions of hypoxia and acidosis, as occur intramuscularly during exercise.

    “The reduction of NO2− to NO is potentiated under conditions of hypoxia [85] and acidosis [86], as are known to occur intramuscularly during exercise [87].”

    From Effects of Dietary Nitrate Supplementation on Weightlifting Exercise Performance in Healthy Adults: A Systematic Review (2020) · cites this paper as [87]

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Research works printed but not linked: 1

  1. Hultman, E., J. Bergstrom, and N. Anderson. 1967. Breakdown and resyn- thesis of phosphoylctreatine and adenosine triphosphate in connection with muscu- lar work in man. Scand. J. Clin. Lab. Invest. 19(1):55-66.

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Related

Authors
Richardson, R. S., Noyszewski, E. A., Kendrick, K. F., Leigh, J. S., & Wagner, P. D.
Affiliations
University of California System (US)
ORCID
Venue
Journal of Clinical Investigation
Publisher
American Society for Clinical Investigation
Published
1995-10-01
Volume
96
Issue
4
Pages
1916-1926
ISSN
0021-9738 (ISSN-L)
DOI
10.1172/jci118237
PMC
PMC185828
OpenAlex
W2074243670
Cited by
647
References
47
Citations by year
2026: 19 · 2025: 16 · 2024: 29 · 2023: 27 · 2022: 16 · 2021: 19 · 2020: 28 · 2019: 23 · 2018: 20 · 2017: 26 · 2016: 14 · 2015: 31 · 2014: 19 · 2013: 21 · 2012: 24
FWCI
27.28
Type
journal article
Language
en
Open access
Locations
  • Journal of Clinical Investigation (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Tobacco-Related Disease Research Program
  • National Heart, Lung, and Blood Institute (R01HL044125, HL 44125, P01HL017731, HL17731)
Topics
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Hemoglobin structure and function
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › High Altitude and Hypoxia
Keywords
oxygen transport, physical activity, hypoxia, capillary oxygen tension, muscle oxygenation, oxygen diffusion limitation, VO2max, quadriceps, arterial oxygen tension, 1H NMR, trained men
MeSH terms
Adult, Biological Transport, Humans, Hydrogen-Ion Concentration, Leg, Male, Muscles, Myoglobin, Oxygen, Oxygen Consumption, Exercise, Cell Respiration

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