Ventilatory support or respiratory muscle training as adjuncts to exercise in obese CPAP-treated patients with obstructive sleep apnoea: a randomised controlled trial.

BACKGROUND: Obstructive sleep apnoea (OSA) and obesity are interdependent chronic diseases sharing reduced exercise tolerance and high cardiovascular risk. INTERVENTION: A 3-month intervention with innovative training modalities would further improve functional capacity and cardiovascular health than usual cycle exercise training in already continuous positive airway pressure (CPAP)-treated obese patients with OSA. METHODS: Fifty three patients (35

Physiological correlates to spontaneous physical activity variability in obese patients with already treated sleep apnea syndrome.

BACKGROUND/OBJECTIVES: Physical activity is promoted in patients with sleep disorders and obesity. The aim of the present study was to assess physiological factors influencing objectively measured spontaneous physical activity in already treated patients for obstructive sleep apnea (OSA) by nocturnal continuous positive airway pressure (CPAP). SUBJECTS/METHODS: Fifty-five patients (age = 53 ± 3 years; body mass index (BMI) = 38 ± 3 kg/m2; compliance with CPAP >4 h/night) were prospectively included. Measurements were 5-day actigraphy with metabolic equivalent of task (METs) assessment, body composition, pulmonary function, quadriceps and respiratory muscle strength, exercise capacity (6-min walking distance and maximal aerobic capacity), as well as sleep parameters (sleepiness, duration, oxygen saturation, and micro-arousals during sleep) and quality of life (SF-36 questionnaire). RESULTS: As expected, the number of steps per day (6879 ± 2511) and mean intensity of physical activity (1.38 ± 0.15 METs) were below the recommendations for obese population. In age-adjusted stepwise regression models, peak oxygen consumption (VO2 peak) and peak dyspnea perception during incremental exercise test were independent predictors of the number of steps per day (r = 0.49, p = 0.001) although VO2 peak and peak minute ventilation were independent predictors of intensity of physical activity (in METs/day; r = 0.49, p = 0.001). CONCLUSIONS: In severe obese patients with OSA, exercise capacity, ventilatory requirement, and dyspnea perception were main physiological components of physical activity. These results emphasize the need to consider specific training interventions that increase ability to perform intense physical activity in obese OSA.

Preserved function and reduced angiogenesis potential of the quadriceps in patients with mild COPD.

BACKGROUND: Little is known about limb muscle abnormalities in mild COPD. Inactivity and systemic inflammation could play a role in the development of limb muscle dysfunction in COPD. The objective of the present study was to characterize quadriceps function, enzymatic activities and morphometry, levels of plasma inflammatory markers and physical activity levels in daily life (PAdl) in patients with mild COPD (GOLD 1). METHODS: Mid-thigh muscle cross-sectional area (MTCSA), quadriceps strength, endurance, fiber-type distribution, capillarity, pro-angiogenesis factors (VEGF-A, angiopoietin I and II) and muscle oxidative capacity were assessed in 37 patients with mild COPD and 19 controls. Systemic inflammatory markers (CRP, IL-6, TNF-α, Fibrinogen, SP-D) and PAdl were assessed. RESULTS: MTCSA, quadriceps strength and endurance were not different between COPD and controls. Capillarity and muscle oxidative capacity were all preserved in mild COPD. Reduced pro-angiogenesis factor mRNA expression was seen in COPD. The level of moderately active intensity (>3 METs) was significantly lower in mild COPD and, in multiple regression analyses, the level of physical activity was a determinant of muscle oxidative capacity and capillarization. No between-group differences were found regarding muscle oxidative stress while circulating IL-6 levels were elevated in mild COPD. CONCLUSIONS: The quadriceps muscle function was preserved in mild COPD although a reduced potential for angiogenesis was found. The reduced level of daily activities and evidence of systemic inflammation in these individuals suggest that these factors precede the development of overt limb muscle dysfunction in COPD.