Journal of Applied Physiology, Vol 64, Issue 5 1947-1952, Copyright © 1988 by American Physiological Society
Breath holding during intense exercise: arterial blood gases, pH, and lactate
G. O. Matheson and D. C. McKenzie
Division of Sports Science, University of British Columbia, Vancouver, Canada.
Seven healthy endurance-trained [maximal O2 uptake (VO2max) = 57.1 +/- 4.1
ml.kg-1.min-1)] female volunteers (mean age 24.4 +/- 3.6 yr) served as
subjects in an experiment measuring arterial blood gases, acid-base status,
and lactate changes while breath holding (BH) during intense intermittent
exercise. By the use of a counterbalance design, each subject repeated five
intervals of a 15-s on:30-s off treadmill run at 125% VO2max while BH and
while breathing freely (NBH). Arterial blood for pH, PO2, PCO2, O2
saturation (SO2) HCO3, and lactate was sampled from a radial arterial
catheter at the end of each work and rest interval and throughout recovery,
and the results were analyzed using repeated-measures analysis of variance.
Significant reductions in pHa (delta mean = 0.07, P less than 0.01),
arterial PO2 (delta mean = 24.2 Torr, P less than 0.01), and O2 saturation
(delta mean = 4.6%, P less than 0.01) and elevations in arterial PCO2
(delta mean = 8.2 Torr, P less than 0.01) and arterial HCO3 (delta mean =
1.3 meq/l, P = 0.05) were found at the end of each exercise interval in the
BH condition. All of the observed changes in arterial blood gases and
acid-base status induced by BH were reversed during the rest intervals.
During recovery, significantly (P less than 0.025) greater levels of
arterial lactate were found in the BH condition.(ABSTRACT TRUNCATED AT 250
WORDS)
