Vectorcardiographic Changes During Exercise Test - Correlates to Lactate and Anaerobic Threshold?

The aim of the study was to investigate the correlations between blood lactate concentration, different vector ECG (VECG) parameters, ventilatory parameters and heart rate during exercise and recovery periods. Six (25-37 years old) non athlete, healthy, male subjects participated in the study. All subjects performed two different bicycle ergospirometric protocols (P1 and P2). The aim in using two different protocols was to attain different lactate levels with different heart rate profiles. VECG parameters were observed to be very sensitive to measurement artifacts, and thus, they were not as informative during exercise as heart rate and spirometer parameters. However, during recovery period changes in T-wave angle (θT ) were similar to those in lactate concentration. Correlations between lactate and RR interval were r = -0.72 (P1, p<0.001) and r = -0.53 (P2, p<0.001), whereas between lactate and θT they were r = -0.54 (P1, p<0.001) and r = -0.71 (P2, p<0.001). The correlation between θT and RR interval was very low. The results suggest that VECG parameters is a potential non-invasive tool for recovery monitoring.