Background Reduced exercise capacity is a common feature of many cardiovascular diseases. Quantitative assessment of exercise capacity is usually achieved by measuring peak oxygen consumption (VO2). However, measuring peak VO2 alone neglects the different components of reduced exercise capacity: namely reduced cardiac output (CO) and oxygen extraction (ΔcO2). A better approach would be to simul...

Oxygen consumption (VO2) and carbon dioxide production (VCO2) rates were measured by electronically recording heart rate (HR) and physical activity (PA). Mean daily VO2 and VCO2 measurements by HR and PA were validated in adults (n = 10 women and 10 men) with room calorimeters. Thirteen linear and nonlinear functions of HR alone and HR combined with PA were tested as models of 24-h VO2 and VCO2...

Individual variation in aerobic capacity has been extensively studied, especially with respect to condition, maturity or pathogen infection, and to gain insights into mechanistic foundations of performance. However, its relationship to mate competition is less well understood, particularly for animals in natural habitats. We examined aerobic capacity [maximum rate of O2 consumption (VO2,max) in...

The relationships between muscle capillarization, estimated O2 diffusion distance from capillary to mitochondria, and O2 uptake (VO2) kinetics were studied in 11 young (mean age, 25.9 yr) and 9 old (mean age, 66.0 yr) adults. VO2 kinetics were determined by calculating the time constants (tau) for the phase 2 VO2 adjustment to and recovery from the average of 12 repeats of a 6-min, moderate-int...

Monoclinic VO2(M) in nanostructure is a prototype material for interpreting correlation effects in solids with fully reversible phase transition and for the advanced applications to smart devices. Here, we report a facile one-step hydrothermal method for the controlled growth of single crystalline VO2(M/R) nanorods. Through tuning the hydrothermal temperature, duration of the hydrothermal time ...

carbon paste electrode was modified by disodium 2,4-diamino-7-methylbenzo[g] pteridine-5,10-dioxide to fabricate a sensor for potentiometric determination of vanadyl ion (vo2+) in aqueous medium. the new ligand was synthesized in three steps with high yield. the optimal composition of the carbon paste was made of graphite powder (64.5%), ionophore (16.6%), paraffin oil (17.8%), and sodium tetra...

This study investigates whether a 6-wk intermittent hypoxia training (IHT), designed to avoid reductions in training loads and intensities, improves the endurance performance capacity of competitive distance runners. Eighteen athletes were randomly assigned to train in normoxia [Nor group; n = 9; maximal oxygen uptake (VO2 max) = 61.5 +/- 1.1 ml x kg(-1) x min(-1)] or intermittently in hypoxia ...

BACKGROUND This study was designed to examine whether the coupling between oxygen consumption (VO2) and cardiac output (CO) is maintained during xenon anaesthesia. METHODS We studied the relationship between VO2 (indirect calorimetry) and CO (ultrasound flowmetry) by adding xenon to isoflurane anaesthesia in five chronically instrumented dogs. Different mixtures of xenon (70% and 50%) and iso...

Background. We hypothesized that the effect of pimobendan (UD-CG 115 BS) to increase calcium sensitivity of contractile protein might result in less myocardial oxygen consumption (Vo2) in comparison with dobutamine when they enhance ventricular contractility to the same extent. To examine this hypothesis, we compared the effects of pimobendan and dobutamine on left ventricular contractility and...