The aim of the present study was to investigate the prevalence of muscle weakness and the importance of physical inactivity in cystic fibrosis (CF), and its relationship to exercise tolerance and muscle strength.Exercise tolerance, skeletal and respiratory muscle strength were studied in a group of 64 adults with CF (age 26¡8 yrs, FEV1 % predicted 65¡19) and in 20 age-matched controls. Physical activity (PA) was assessed in 20 patients and all controls.Quadriceps muscle weakness was present in 56% of the patients. Peak oxygen uptake and 6-min walking distance were below normal in 89 and 75% of patients, respectively. Respiratory muscle strength was normal. The differences remained after correcting for PA. Quadriceps force was correlated to the 6-min walking distance but not to peak oxygen uptake. ''Mild'' PA (.3 metabolic equivalents (METS)) and the number of steps overlapped with controls, but CF patients had less moderate PA (.4.8 METS). Moderate PA was related to peak oxygen uptake and quadriceps force.Skeletal muscle weakness and exercise intolerance are prevalent in cystic fibrosis. Physical inactivity is a factor significantly contributing to exercise tolerance and skeletal muscle force in adults with cystic fibrosis, but these impairments are in excess to that expected from physical inactivity only.

The complexity of central breathing disturbances during sleep has become increasingly obvious. They present as central sleep apnoeas (CSAs) and hypopnoeas, periodic breathing with apnoeas, or irregular breathing in patients with cardiovascular, other internal or neurological disorders, and can emerge under positive airway pressure treatment or opioid use, or at high altitude. As yet, there is insufficient knowledge on the clinical features, pathophysiological background and consecutive algorithms for stepped-care treatment. Most recently, it has been discussed intensively if CSA in heart failure is a "marker" of disease severity or a "mediator" of disease progression, and if and which type of positive airway pressure therapy is indicated. In addition, disturbances of respiratory drive or the translation of central impulses may result in hypoventilation, associated with cerebral or neuromuscular diseases, or severe diseases of lung or thorax. These statements report the results of an European Respiratory Society Task Force addressing actual diagnostic and therapeutic standards. The statements are based on a systematic review of the literature and a systematic two-step decision process. Although the Task Force does not make recommendations, it describes its current practice of treatment of CSA in heart failure and hypoventilation.

Full author information is available at the end of the article Greet Van den Berghe, Alexander Wilmer, Rik Gosselink and Greet Hermans have equally contributed. The members of the COVID-19 consortium are listed in "Acknowledgements".

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BackgroundAdult patients with cystic fibrosis have peripheral muscle weakness, which is related to exercise intolerance and poor prognosis. The influence of acute exacerbations on muscle strength has been poorly studied. This study aimed to investigate whether quadriceps force (QF), as assessed with an involuntary technique, changes during intravenous antibiotics therapy (IVAT) for an exacerbation.MethodsQF was measured in 20 patients using twitch stimulation of the femoral nerve at the day of hospitalization (day 1) and at termination (day 14) of the IVAT. Physical activity was monitored during IVAT using a SenseWear armband. Ten stable patients served as control subjects.ResultsQF did not change during exacerbation (potentiated twitch force at day 1: 140 ± 42 N, at day 14: 140 ± 47 N), but a decrease was observed in individual patients. Changes in twitch force during exacerbation were correlated with time spent in activities of at least moderate intensity (r = 0.61, p = 0.007).ConclusionsQF does not systematically decrease during exacerbations of cystic fibrosis. Individual changes in QF are well correlated with daily time spent in activities of at least moderate intensity.