Clinical Research Directory

Influence of Intermittent Hypoxia on Loop Gain in Healthy Subjects

Sleep apnoea-hypopnoea syndrome (SAHOS), which causes numerous comorbidities, particularly cardiovascular ones, is widespread worldwide today and incurs significant healthcare costs. Current research in this field focuses on identifying different phenotypes in affected patients in order to provide more personalised treatment. One of these phenotypes appears to be linked to instability in ventilatory control due to an increase in loop gain (LG) in these subjects. However, the pathophysiology of this ventilatory control instability due to increased LG is not fully understood. It is still difficult to determine whether subjects have an intrinsically high LG or if exposure to intermittent hypoxia during OSA promotes an increase in LG. It has also been demonstrated that OSA causes vascular hyperreactivity by increasing oxidative stress through elevated ROS production. This leads to endothelial dysfunction in response to intermittent hypoxia associated with apnoea. Extracellular vesicles (microvesicles and exosomes) have been shown to play a role in this endothelial response. These extracellular vesicles are essential for intercellular communication in both physiological and pathological situations, such as SAHOS. Therefore, the objective of this research is to determine whether exposure to intermittent hypoxia and changes in microvesicle phenotype could influence LG, which could lead to new therapeutic advances in the context of SAHOS.

CPOD Patient's Tolerance of Intermittent Exercise With Inter-exercise Recovery Under Normoxic Hypoxia

Exercise retraining improves the prognosis and quality of life of patients with chronic lung or circulatory diseases. However, exercise intolerance may be caused by excessive ventilatory. Exposure to oxygen-replete air reduces this ventilatory overload, improves sleep and enhances responses to exercise. This study examine the impact of the acute manipulation of oxygen availability during inter-exercise recovery period of an intermittent cycling exercise on perceptual responses. this randomized, controlled, study include adult patient with COPD. On separate days, 50 patients with COPD completed four sets of 4-min at 85% of VO2peak intercept by 3-min of passive recovery in two randomized between-sets recovery conditions. Rating exertion perception, gaz exchanges, heart rate, sleep quality and nocturnal heart rate variability were assessed. Hypoxic exposure during inter-repetition recovery phases would reduce the ventilatory load during exercise. What's more, patients would not be forced to perform the sporting gesture in a restricted space or wearing a mask, limiting dyspnea and the perceived difficulty of the effort. Lastly, the induction of hypoxic stress during the re-training session helped to improve patients' sleep.