Active And Passive Recovery & Acid-base Kinetics Following Multiple Bouts Of Intense Exercise

Purpose The purpose of the present study was to compare the effect of active vs. passive recovery on acid-base kinetics during multiple bouts of intense exercise. Methods Ten healthy male subjects [30±6.8yrs, 180.25±7.5cm, 76.3±9.7kg, 11.6±4.3%BF] completed four exercise trials. Two of the trials consisted of 3 exercise bouts to exhaustion (%110 workload max) with either 15 minute active (20% workload max) or passive (seated) recovery between bouts. Results No difference was found between active and passive recovery conditions for recovery kinetics (slope & halftime to recovery) of blood pH, lactate, bicarbonate (HCO3), or base excess (BE). Passive recovery caused increased blood acidosis between trials when compared to active recovery for both low pH and end recovery values (F(2,18)=5.96; p<0.01 & (F(2,18)=8.95; p<0.01). No difference between VO2, accumulated oxygen deficit (AOD), and performance were found between recovery conditions. Conclusion Acid-base recovery from intermittent, intense exercise to exhaustion is altered by mode of recovery. Blood pH recovery during an active condition is similar during 3 successive bouts to exhaustion, while passive recovery elicits a continual increase in blood acidosis. Multiple bout performance may not be dependent upon blood acid-base balance, however further study using similar methodology should compare muscle and blood acid-base changes to determine indices of fatigue associated with such exercise.