Hyperoxia-induced alterations in cardiovascular function and autonomic control during return to normoxic breathing.

Hyperoxia causes hemodynamic alterations. We hypothesized that cardiovascular and autonomic control changes last beyond the end of hyperoxic period into normoxia. Ten healthy volunteers were randomized to breathe either medical air or 100% oxygen for 45 min in a double-blind study design.

A 5-month weight-reduction programme has a positive effect on body composition, aerobic fitness, and habitual physical activity of severely obese girls: a pilot evaluation study.

In this pilot study, we wished to determine whether a 5-month multidisciplinary programme of a combined dietary-nutritional education-exercise intervention would have favourable effects on the health status of 18 obese adolescent girls. Before and after the clinical intervention, body composition and habitual physical activity were assessed by bioelectrical impedance and accelerometry, respectively. Aerobic fitness and substrate utilization were determined by gas exchange using an incremental field test that mimics habitual conditions.

Combination of two oxidant stressors suppresses the oxidative stress and enhances the heat shock protein 27 response in healthy humans.

We tested the hypothesis that the combination of 2 oxidant stressors (hyperoxia and fatiguing exercise) might reduce or suppress the oxidative stress. We concomitantly measured the plasma concentration of heat shock proteins (Hsp) that protect the cells against the deleterious effects of reactive oxygen species. Healthy humans breathed pure oxygen under normobaric condition for 50-minute periods during which they stayed at rest or executed maximal static handgrip sustained until exhaustion.

Arterial compliance in divers exposed to repeated hyperoxia using rebreather equipment.

Background: Acute hyperoxic exposure is known to modify cardiovascular parameters like a decrease in cardiac output, arterial vasoconstriction, and autonomic nervous system changes. We hypothesized that repeated hyperbaric hyperoxic exposures, as experienced by military oxygen divers, lead to long-term arterial alterations.

Methods: Arterial blood pressure measurements and pulse wave velocity (PWV) recordings were performed during basal conditions in 15 elite military oxygen divers, and compared to 15 non-diver controls.

Haemodynamic changes after prolonged water immersion.

Thermoneutral water immersion increases cardiac preload and changes the neuroendocrine settings of blood volume regulation. The resulting marked diuresis may lead to significant haemodynamic changes after the end of a prolonged water immersion. Ten volunteers underwent 6 h of complete thermoneutral water immersion.

Diaphragmatic motion studied by m-mode ultrasonography: methods, reproducibility, and normal values.

Background: Although diaphragmatic motion is readily studied by ultrasonography, the procedure remains poorly codified. The aim of this prospective study was to determine the reference values for diaphragmatic motion as recorded by M-mode ultrasonography.

Methods: Two hundred ten healthy adult subjects (150 men, 60 women) were investigated.