SHORT ENDURANCE TRAINING IMPROVES LACTATE REMOVAL ABILITY IN PATIENTSWITH HEART-TRANSPLANTS

Eight male patients with heart transplants at least a year after the o peration were submitted to a 6-wk endurance training program and explo red for their blood lactate kinetics before and after exercise. The te sts consisted of a bicycle exercise upgraded by 20 W every 2 min until volitional fatigue. Training induced a significant (P < 0.025) decrea se in lactate concentrations from the 40-W to the 120-W exercise step and a significant increase (P < 0.025) in the time into exercise (9.87 +/- 0.87 min vs 7.17 +/- 0.90 min) at which a lactate concentration o f 2 mmol . l(-1) was reached. Lactate recovery curves were significant ly lower (P < 0.036) after training than before training, except at mi nutes 1, 2, 8, and 60. The fits of a biexponential mathematical model to the lactate recovery curves reveal a significant (P < 0.036) traini ng-induced increase (+71%) in the slow-velocity constant gamma(2)v of the model. In view of the functional meaning given to this parameter, namely the ability to remove lactate, it is concluded that training lo wers blood lactate concentrations during exercise and recovery in pati ents with heart transplants at least in part by raising the efficiency with which lactate is removed, and that the ability to remove lactate can be a valuable criterion to evaluate physical fitness.