Exercise-induced intrapulmonary arteriovenous shunting, as detected by saline contrast echocardiography, has been demonstrated in healthy humans. We have previously suggested that increases in both pulmonary pressures and blood flow associated with exercise are responsible for opening these intrapulmonary arteriovenous pathways. In the present study, we hypothesized that, although cardiac outpu...

Preventive effects of acetazolamide (ACZ) on acute mountain sickness (AMS) are well established but effects on exercise performance at high altitude or in hypoxia have been less considered and are still inconsistent. We hypothesized that low-dose ACZ would not impair exercise performance at simulated high altitude. Thus, the aim of this study was to evaluate the interaction between low-dose ACZ...

Phosphocreatine (PCr) was reduced to equivalent levels in carp white muscle by high-intensity exhaustive exercise and exposure to hypoxia at 15 degrees C and 25 degrees C in order to assess the influence of intracellular pH (pH(i)), temperature and lactate levels on PCr recovery in vivo. High-intensity exercise resulted in a significantly lower pH(i) compared with hypoxia exposure and the rate ...

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 ...

This study examined exercise-induced hypoxaemia (EIH) and plasma volume contraction as modulators of serum erythropoietin (Epo) production. Five athletes cycled for 3 min at supra-maximal power outputs, at each of two different elevations (1,000 m and 2,100 m). Five subjects were exposed to normobaric hypoxia (F(I)O(2)=0.159), seven subjects underwent plasmapheresis to reduce plasma volume and ...

The present study investigated whether maximal in vitro Na-K-ATPase activity in human skeletal muscle is changed with exercise and whether it was altered by acute hypoxia. Needle biopsies from 14 subjects were obtained from vastus lateralis before and after 4 min of intense muscle activity. In addition, six subjects exercised also in hypoxia (12.5% oxygen). The Na-K-ATPase assay revealed a 19% ...

We measured oxygen consumption during walking per unit distance (Cw) values for 12 human healthy young males at six speeds from 0.667 to 1.639 m s-1 (four min per stage) on a level gradient under normobaric normoxia, moderate hypoxia (15% O2), and severe hypoxia (11% O2). Muscle deoxygenation (HHb) was measured at the vastus lateralis muscle using near-infrared spectroscopy. Economical speed wh...

the aim of this study was to investigate the effect of a period of interval training and step taper on weight changes and endurance performance in male rats during puberty. in this experimental study, 40 male wistar rats (3 weeks old) were randomly divided into exercise and control groups. after 6 weeks of incremental interval training, exercise group was divided in to 3 groups of 3-week taper ...

Introduction: Prolonged and intermittent oxygen pre-exposure is associated with protection against ischemic reperfusion (IR) injury. In the current study, attempts were made to investigate the relationship between exposure to prolonged and intermittent normobaric hyperoxia (NBHO) and expression of excitatory amino acids transporters (EAATs) and TNF-α level. Method: Rats were divided into fo...