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: Partition of plasma hydrogen ion concentration changes during repeated sprints.
    Author: Kronfeld DS, Ferrante PL, Taylor LE, Tiegs W.
    Journal: Equine Vet J Suppl; 1999 Jul; (30):380-3. PubMed ID: 10659286.
    Abstract:
    Increases in blood [H+] and lactic acid [La-] attend fatigue. We applied Stewart's physiological model of acid-base status and simple regressions to assess the importance of independent variables and [La-] on [H+] during repeated sprints. Eight well-conditioned Arabians performed 9 sprints. Plasma from jugular vein samples was analysed for pH, PCO2, Na+, K+ and Cl-. Plasma [La-] was calculated from blood [La-], plasma [H+] from pH, SID from Na+, K+, Cl- and La-, Atot from pH, PCO2 and SID. Peaks for SID, PCO2 and [H+] were reached at sprint 1, -2 and -3, respectively. At sprint 3, the 5.7 nmol/l peak in [H+] was partitioned into 2.3, 2.7 and 0.7 nmol/l for Atot, PCO2 and SID, respectively. From sprint 3 to sprint 9, increases in Atot and decreases in SID tended to increase [H+] but were counteracted by a steady decrease in PCO2 that determined the progressive decrease in [H+]. Therefore PCO2 was the dominant determinant of [H+] during 9 repeated sprints, and the expected major effect of [La-] was moderated in the SID by opposing increases in [Na+] and [K+]. In the work-adapted phase (sprints 3-9), decreasing [H+] was correlated positively with PCO2 (r = 0.997, P < 0.001) but negatively with La- (r = -0.986, P < 0.001). Respiration was therefore completely compensating for the effects of metabolism on [H+]. During the transition from rest to sprint 3 (peak plasma [H+]), increasing [H+] was highly correlated (r = 0.99, P = 0.011) with [La-] but no other variable. The empirical and physiological analyses were consistent with one another during the work-adapted phase, but emphasis was placed on [La-] by the regression analysis, in contrast to PCO2 by the Stewart analysis, during the rest-work transition.
    [Abstract] [Full Text] [Related] [New Search]