Physicochemical analysis of acid-base status during recovery from high- intensity exercise in Standardbred racehorses

摘要

The present study used the physicochemical approach to characterize the changes in acid-base status that occur in Standardbred racehorses during recovery from high-intensity exercise. Jugular venous blood was sampled from nine Standardbreds in racingcondition, at rest and for 2 h following a high-intensity training workout. Plasma [H~+] increased from 39.1 ± l.Oneq l~(-1) at rest to 44.8 ± 2.7neq l~(-1) at 1 min of recovery. A decreased strong ion difference ([SID]) was the primary contributor tothe increased [H~+] immediately at the end of exercise, while increased plasma weak ion concentration ([A_(tot)]) was a minor contributor to the acidosis. A decreased partial pressure of carbon dioxide (PCO_2) at 1 min of recovery had a slight alkalinizing effect. The decreased [SID] at 1 min of recovery was a result of a 15.1 ± 3.l meq l~(-1) increase in [lactate~-], as [Na~+] and [K~+] were also increased by 6.5 ± 0.7 and 1.14 ± 0.06 meq l~(-1), respectively, at 1 min of recovery. It is concluded that high-intensity exercise and recovery is associated with significant changes in acid-base balance, and that full recovery of many parameters that determine acid-base status requires 60-120 min.