Journal of Applied Physiology, Vol 48, Issue 2 236-242, Copyright © 1980 by American Physiological Society
Hemoglobin affinity for oxygen during short-term exhaustive exercise
J. P. Klein, H. V. Forster, R. D. Stewart and A. Wu
We assessed hemoglobin affinity for oxygen (standard P50: pH 7.40, PCO2 40
Torr, temperature 37 degrees C) in 3 series of studies of 16 male subjects
who performed exhaustive treadmill exercise of 10 min duration. Standard
P50 was significantly elevated (0.7--2.5 Torr) during the last minute of
and for 30 min following exercise. Exercise while carboxyhemoglobin (HbCO)
was acutely elevated to 5% did not affect std P50 any differently than
exercise alone. 2,3-Diphosphoglycerate (2,3-DPG) was significantly elevated
after exercise, but not during or 30 min postexercise, and it correlated
significantly with P50 in 2 studies (r, 0.43--0.68). ATP (mumol/100 ml) was
significantly elevated only 3 min postexercise. Serum [Na+], [K+], [Cl-],
osmolarity, and hemoglobin (Hb) concentration were significantly elevated
during exercise with [Na+] osmolarity, and [Hb] remaining significantly
elevated postexercise. There was no significant correlation between std P50
and any of these variables. Multiple correlation regression analysis
between P50 and 2,3-DPG, ATP, and [Na+] yields a coefficient of 0.86. We
conclude this type of exercise is unique in causing a small change in std
P50 that appears to be mediated by several factors.
