Acid-base changes in the running greyhound: contributing variables.

To determine the factors responsible for changes in H+] during and after sprint exercise in the racing greyhound, Stewart's quantitative acid-base analysis was applied to arterial blood plasma samples taken at rest, at 8-s intervals during exercise, and at various intervals up to 30 min after a 402-m spring (approximately 30 s) on the track. Na+], K+], Cl-], total Ca], lactate], albumin], Pi], PCO2, and pH were measured, and the H+] was calculated from Stewart's equations. This short sprint caused all measured variables to change significantly. Maximal changes were strong ion difference decreased from 36.7 meq/l at rest to 16.1 meq/l; albumin] increased from 3.1 g/dl at rest to 3.7 g/dl; PCO2, after decreasing from 39.6 Torr at rest to 27.9 Torr immediately prerace, increased during exercise to 42.8 Torr and then again decreased to near 20 Torr during most of recovery; and H+] rose from 36.6 neq/l at rest to a peak of 76.6 neq/l. The H+] calculated using Stewart's analysis was not significantly different from that directly measured. In addition to the increase in lactate and the change in PCO2, changes in albumin], Na+], and Cl-] also influenced H+] during and after sprint exercise in the running greyhound.