Endurance training significantly decreased the VO2 slow component (P<0.05), an adaptation attributable to factors other than reductions in plasma epinephrine, blood lactate, and ventilation.
Does endurance training reduce the VO2 slow component during heavy exercise in untrained males?
Endurance training rapidly attenuates the VO2 slow component during heavy exercise, but this adaptation is not driven by reductions in plasma epinephrine, blood lactate, or ventilation.
p-value: p=<0.05
Seven untrained male subjects age 25.6 +/- 1.5 (SE) yr, peak O2 uptake (VO2) 3.20 +/- 0.19 l/min trained on a cycle ergometer 4 days/wk for 6 wk, with the absolute training workload held constant for the duration of training. Before and at the end of each week of training, the subjects performed 20 min of constant-power exercise at a power designed to elicit a pronounced slow component of VO2 (end-exercise VO2-VO2 at minute 3 of exercise) in the pretraining session. An additional 20-min exercise bout was performed after training at this same absolute power output during which epinephrine (Epi) was infused at a rate of 100 ng.kg-1.min-1 between minutes 10 and 20. After 2 wk of training, significant decreases in VO2 slow component, end-exercise VO2, blood lactate (La- and glucose concentrations, plasma Epi (Epi) and norepinephrine concentrations, ventilation (VE), and heart rate (HR) were observed (P < 0.05). Although the rapid attenuation of the VO2 slow component coincided temporally with reductions in plasma Epi, blood La-, and VE, the infusion of Epi after training significantly increased plasma Epi (delta 2.22 ng/ml), blood La- (delta 2.4 mmol/l) and VE (delta 10.0 l/min) without any change in exercise VO2. We therefore conclude that diminution of the VO2 slow component with training is attributable to factors other than the reduction in plasma Epi, blood La- and VE.
Womack et al. (Fri,) conducted a other in Untrained healthy subjects (n=7). Endurance training vs. Pre-training baseline was evaluated on VO2 slow component (p=<0.05). Endurance training significantly decreased the VO2 slow component (P<0.05), an adaptation attributable to factors other than reductions in plasma epinephrine, blood lactate, and ventilation.