Endurance training regimen based upon arterial blood lactate: effects on anaerobic threshold

The purpose of this investigation was to assess the effect of endurance training based upon the intensity as determined by the arterial blood lactate concentration (LA). Seven healthy male college students performed endurance training on a Monark bicycle ergometer for 15 min on 3 days/week for 8 weeks, at an intensity corresponding to 4 mmol X l-1 arterial blood LA determined during an incremental exercise test (25 watts increment every minute on a bicycle at 50 rpm). Another six male students served as the control group. To assess the training effect, both an incremental exercise test and a submaximal exercise test were performed before and after the endurance training. In the incremental exercise test, VO2max, VE at VO2max, anaerobic threshold (AT), and the onset of respiratory compensation for metabolic acidosis (RCMA) were measured. AT was determined as the point at which arterial LA rose above the resting value, and RCMA was determined as the point at which Paco2 decreased during the incremental exercise test. After training, AT increased significantly (37% increment expressed in VO2, p less than 0.05). There was a significant increase (p less than 0.05) in RCMA (17%) and VO2max (14%). This training decreased VO2 (4%), VE (15%), heart rate (10%), respiratory exchange ratio (5%), and LA (23%) significantly (p less than 0.05) during the submaximal exercise test after training. On the other hand, there were no significant changes in the control group through the period when the training group performed their training. These results showed that the endurance training intensity corresponding to 4 mmol X l-1 arterial blood LA was effective for the improvement in AT as well as VO2max. It is suggested that the present training regimen could delay the onset of anaerobic glycolysis, thus shifting AT to the higher workload and decreasing LA at a given submaximal exercise after training.