Kinetics of VO(2) limb blood flow and regional muscle deoxygenation in young adults during moderate intensity, knee-extension exercise. European journal of applied physiology [Eur J Appl Physiol] Journal article | | Title | Kinetics of VO(2) limb blood flow and regional muscle deoxygenation in young adults during moderate intensity, knee-extension exercise. | | Author(s) | Dumanoir GR, Delorey DS, Kowalchuk JM, Paterson DH | | Institution | School of Kinesiology, Canadian Centre for Activity and Aging, The University of Western Ontario, London, ON, N6A-3K7, Canada. | | Source | Eur J Appl Physiol 2009 Oct 31. | | Abstract | The kinetics of pulmonary O(2) uptake [Formula: see text] limb blood flow (LBF) and deoxygenation (DeltaHHb) of the vastus lateralis (VL) and vastus medialis (VM) muscles during the transition to moderate-intensity knee-extension exercise (MOD) was examined. Seven males (27 +/- 5 years; mean +/- SD) performed repeated step transitions (n = 4) from passive exercise to MOD. Breath by breath [Formula: see text] femoral artery LBF, and VL and VM muscle HHb were measured, respectively, by mass spectrometer and volume turbine, Doppler ultrasound and near-infrared spectroscopy. Phase 2 [Formula: see text] LBF, and HHb data were fit with a mono-exponential model. The time constant (tau) of the [Formula: see text] and LBF response were not different ([Formula: see text] 24 +/- 6 s; tauLBF, 23 +/- 8 s). The HHb response did not differ between VL and VM in amplitude (VL 6.97 +/- 4.22 a.u.; VM 7.24 +/- 3.99 a.u.), time delay (HHb(TD): VL 17 +/- 2 s; VM 15 +/- 1 s), time constant (tauHHb: VL 11 +/- 6 s; VM 13 +/- 4 s), or effective time constant [tau'HHb (= HHb(TD) + tauHHb): VL 28 +/- 7 s; VM 28 +/- 4 s]. Adjustments in HHb in VL and VM depict a similar balance of regional O(2) delivery and utilization within the quadriceps muscle group. The tau'HHb and [Formula: see text] were similar, however, the HHb displayed an "overshoot" relative to the steady-state levels reflecting a slower alteration of microvascular blood flow (O(2) delivery) relative to O(2) utilization, necessitating a greater reliance on O(2) extraction. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19882164 |
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