Effects of the Turbine™ on Ventilatory and Sensory Responses to Incremental Cycling.

Introduction: The Turbine™ is a nasal dilator marketed to athletes to increase airflow, which may serve to reduce dyspnea and improve exercise performance, presumably via reductions in the work of breathing (WOB). However, the unpublished data supporting these claims were collected in individuals at rest that were exclusively nasal breathing. These data are not indicative of how the device influences breathing during exercise at higher ventilations when a larger proportion of breathing is through the mouth.

Day-to-day variability in cardiorespiratory responses to hypoxic cycle exercise.

Repeatedly performing exercise in hypoxia could elicit an independent training response and become an unintended co-intervention. The primary purposes of this study were to determine if hypoxic exercise responses changed across repeated testing and to assess the day-to-day variability of commonly used measures of cardiorespiratory and metabolic responses to hypoxic exercise. Healthy young males (aged 23 ± 2 years) with a maximal O2 consumption of 50.

Anti-oxidant N-acetylcysteine diminishes diesel exhaust-induced increased airway responsiveness in person with airway hyper-reactivity.

Background: Inhalation of diesel exhaust (DE) at moderate concentrations causes increased airway responsiveness in asthmatics and increased airway resistance in both healthy and asthmatic subjects, but the effect of baseline airway responsiveness and anti-oxidant supplementation on this dynamic is unknown.

Objectives: We aimed to determine if changes in airway responsiveness due to DE are attenuated by thiol anti-oxidant supplementation, particularly in those with underlying airway hyper-responsiveness.

Methods: Participants took N-acetylcysteine (600 mg) or placebo capsules three times daily for 6 days.

Haematological acclimation and re-acclimation to hypoxia in the mouse.

Haematological responses throughout 4 w of initial acclimation (IA) and three paradigms of re-acclimation (RA) to hypoxia (FI(O₂)) were examined in female mice. We hypothesised that (i) haematological responses would be increased during re-exposure, resulting in greater O₂-carrying capacity in RA compared to IA; and (ii) further improvements would occur when abbreviating the de-acclimation period to 1 w (RA↓DA) or extending the IA period to 8 w (RA↑IA). The serum [EPO] response was blunted in all RA groups compared to IA but the resulting reticulocyte response was similar in all experimental groups.

Acclimatisation in trekkers with and without recent exposure to high altitude.

In mountaineers, recent altitude exposure has been shown to improve climbing performance and clinical outcomes during re-exposure to high altitude. However, the timing of previous altitude exposure has not been clearly reported and previous findings might be driven by individuals who were still acclimatised at the time of re-exposure. Our goal was to determine whether recent altitude exposure would confer an advantage even in individuals who had de-acclimatised for ≥ 1 week before being re-exposure.

Resting and exercise ventilatory chemosensitivity across the menstrual cycle.

We hypothesized that resting and exercise ventilatory chemosensitivity would be augmented in women when estrogen and progesterone levels are highest during the luteal phase of the menstrual cycle. Healthy, young females (n = 10; age = 23 ± 5 yrs) were assessed across one complete cycle: during early follicular (EF), late follicular (LF), early luteal, and mid-luteal (ML) phases. We measured urinary conjugates of estrogen and progesterone daily.

The pulmonary system during exercise in hypoxia and the cold.

The demands for pulmonary O(2) and CO(2) transport in the exercising human are substantial. Fortunately, the regulatory and architectural limits of the pulmonary system meet the requirements of heavy exercise in most individuals. However, in some highly trained athletes the high metabolic demand of intense exercise is in excess of the capacity of the pulmonary system.

Performance of evacuated blood collection tubes at high altitude.

Researchers and clinicians may not be aware that the performance of evacuated blood collection systems is impaired at high altitude. We tested four sizes of Vacutainer tubes at altitudes ranging from sea level to 5341 m to and determined that draw volumes are reduced by approximately 0.5 mL for every 1000 m gain in terrestrial elevation.

Control of ventilation in humans following intermittent hypoxia.

Exposure to chronic or intermittent hypoxia produces alterations in the ventilatory response to hypoxia. These adaptations can differ depending on the severity of the hypoxic stimulus, its duration, its pattern, and the presence or absence of other chemical stimuli. As such, there are significant differences between the responses to intermittent versus continuous hypoxia.

Lung density is not altered following intense normobaric hypoxic interval training in competitive female cyclists.

Noninvasive imaging techniques have been used to assess pulmonary edema following exercise but results remain equivocal. Most studies examining this phenomenon have used male subjects while the female response has received little attention. Some suggest that women, by virtue of their smaller lungs, airways, and diffusion surface areas may be more susceptible to pulmonary limitations during exercise.