These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Lactic acidosis as a facilitator of oxyhemoglobin dissociation during exercise.
    Author: Stringer W, Wasserman K, Casaburi R, Pórszász J, Maehara K, French W.
    Journal: J Appl Physiol (1985); 1994 Apr; 76(4):1462-7. PubMed ID: 8045820.
    Abstract:
    The slow rise in O2 uptake (VO2), which has been shown to be linearly correlated with the increase in lactate concentration during heavy constant work rate exercise, led us to investigate the role of H+ from lactic acid in facilitating oxyhemoglobin (O2Hb) dissociation. We measured femoral venous PO2, O2Hb saturation, pH, PCO2, lactate, and standard HCO3- during increasing work rate and two constant work rate cycle ergometer exercise tests [below and above the lactic acidosis threshold (LAT)] in two groups of five healthy subjects. Mean end-exercise femoral vein blood and VO2 values for the below- and above-LAT square waves and the increasing work rate protocol were, respectively, PO2 of 19.8 +/- 2.1 (SD), 18.8 +/- 4.7, and 19.8 +/- 3.3 Torr; O2 saturation of 22.5 +/- 4.1, 13.8 +/- 4.2, and 18.5 +/- 6.3%; pH of 7.26 +/- 0.01, 7.02 +/- 0.11, and 7.09 +/- 0.07; lactate of 1.9 +/- 0.9, 11.0 +/- 3.8, and 8.3 +/- 2.9 mmol/l; and VO2 of 1.77 +/- 0.24, 3.36 +/- 0.4, and 3.91 +/- 0.68 l/min. End-exercise femoral vein PO2 did not differ statistically for the three protocols, whereas O2Hb saturation continued to decrease for work rates above LAT. We conclude that decreasing capillary PO2 accounted for most of the O2Hb dissociation during below-LAT exercise and that acidification of muscle capillary blood due to lactic acidosis accounted for virtually all of the O2Hb dissociation above LAT.
    [Abstract] [Full Text] [Related] [New Search]