Speeding of VO2 kinetics in response to endurance-training in older and young women

The goal of this study was to examine the time-course of changes in oxygen uptake kinetics ( τV O 2p ) during step-transitions from 20 W to moderate-intensity cycling in response to endurance-training in older (O) and young (Y) women. Six O (69 ± 7 years) and 8 Y (25 ± 5 years) were tested pre-training, and at 3, 6, 9, and 12 weeks of training. V O 2p was measured breath-by-breath using a mass spectrometer. Changes in deoxygenated-hemoglobin concentration of the vastus lateralis (∆[HHb]) were measured by near-infrared spectroscopy in Y (but this was not possible in O). V O 2p and ∆[HHb] were modeled with a mono-exponential. Training was performed on a cycle-ergometer three times per week for 45 min at ~70% of V O 2peak . Pre-training τV O 2p was greater ( p