Respiratory gas exchanges, heart rate and blood lactate kinetics during and after the repetition of supramaximal individualized exercises in trained and untrained subjects

Objective. - Determine the kinetics of gas exchange, heart rate (HR) and blood lactate concentration [La] during and after supramaximal intermittent individualized exercises in trained (TR) and untrained (UTR) subjects. Methods.- 14 subjects (7 trained and 7 untrained subjects) performed three repetitions of an exercise corresponding to 60% of time to exhaustion at 120% of the aerobic maximum power on a cycle ergometer (MedGraphics/Excalibur, USA). The two first exercises were separated by 5 min recovery. The third exercise was followed by 20 min recovery. The oxygen uptake was measured continuously using a breath by breath device (Medgraphics/CPX). Blood was taken from fingers during recoveries for lactate analyzis. Results. - Results showed that oxygen uptake (VO ₂ ml/minute, P <0.01), carbon dioxide (VCO₂ ml/minute, P <0.05), ventilation (VEl/minute, P <0.01) were significantly higher in trained than untrained subjects during the third supramaximal exercise. However, HR and [La] values were not significantly different in both groups. During the recovery, the percent of VO₂ recovery was higher in TR subjects than UTR (75 vs 59.55% respectively, P <0.05) during the first minute of recovery.After the first minute, differences were not statistically different. The percent of VCO₂, VE and HR recovery was also significantly higher in TR during the first and the second minute of recovery. After the 2nd minute, differences were not significant. Conclusion. - Although they showed higher values of VO₂, VCO₂, and VE, during supramaximal intermittent exercise, trained subjets demonstrated sooner capacity to recover than untrained subjects. Trained subjets were able to reduce their metabolism during recovery more than untrained subjects after the repetition of supramaximal individualized exercise bouts.