European journal of applied physiology
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Eur. J. Appl. Physiol. · Dec 2016
Validity of a perceptually-regulated step test protocol for assessing cardiorespiratory fitness in healthy adults.
To determine whether maximal oxygen uptake (VO2max) could be predicted accurately and reliably from a 2-step, perceptually-regulated exercise test (PRET) in healthy adults. ⋯ The step PRET elicited significant and reliable increases in VO2 across the four RPE levels, but under-estimated treadmill VO2max. However, there was better agreement between measured and predicted VO2max when extrapolated to HRmax. As evidence indicates the underestimation of VO2max is explained by the difference in the mode of exercise, the step PRET provides a simple and convenient test of cardiorespiratory fitness.
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Eur. J. Appl. Physiol. · Dec 2016
Randomized Controlled TrialHigh-intensity Interval training enhances mobilization/functionality of endothelial progenitor cells and depressed shedding of vascular endothelial cells undergoing hypoxia.
Exercise training improves endothelium-dependent vasodilation, whereas hypoxic stress causes vascular endothelial dysfunction. Monocyte-derived endothelial progenitor cells (Mon-EPCs) contribute to vascular repair process by differentiating into endothelial cells. This study investigates how high-intensity interval (HIT) and moderate-intensity continuous (MCT) exercise training affect circulating Mon-EPC levels and EPC functionality under hypoxic condition. ⋯ HIT is superior to MCT for improving hemodynamic adaptation and Mon-EPC production. Moreover, HIT effectively enhances EPC functionality and suppresses endothelial injury undergoing hypoxia.
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Eur. J. Appl. Physiol. · Dec 2016
Comparative StudyCardiac stroke volume variability measured non-invasively by three methods for detection of central hypovolemia in healthy humans.
Hypovolemia decreases preload and cardiac stroke volume. Cardiac stroke volume (SV) and its variability (cardiac stroke volume variability, SVV) have been proposed as clinical tools for detection of acute hemorrhage. We compared three non-invasive SV measurements and investigated if respiration-induced fluctuations in SV may detect mild and moderate hypovolemia in spontaneously breathing humans. ⋯ Cardiac stroke volume estimated by ultrasound Doppler and by arterial blood pressure curve showed parallel variations beat-to-beat during simulated hemorrhage, whereas impedance cardiography did not appear to track beat-to-beat changes in cardiac stroke volume. The variability in cardiac stroke volume was decreased during mild and moderate hypovolemia and could be used for early detection of hypovolemia.