The Study of Skeletal Muscle Function in Obstructive Sleep Apnea
Condition: Obstructive Sleep Apnea
MeSH terms: Apnea; Sleep Apnea Syndromes; Sleep Apnea, Obstructive
Study type: Interventional

Summary: 
      The purposes of this study includes (1)to investigate inspiratory muscles and non-inspiratory
      muscle function in terms of strength, endurance, and fatigability in patients with
      obstructive sleep apnea (OSA), (2) investigate the metabolic characteristics of peripheral
      muscles and biochemistry markers in patients with OSA, and (3) to detect the effect of
      exercise training on the measured parameters in patients with OSA.
    

Detailed description: 
      It has become increasingly recognized that skeletal muscle abnormalities are common and
      profound in patients with chronic inflammatory status. Based on the unique character of
      obstructive sleep apnea (OSA), repeated intermittent apnea and hypopnea caused by the upper
      airway muscles collapse during inspiration, it is logical to speculate some adaptations in
      skeletal muscle of patients with OSA. The purpose of the first part is to investigate the
      inspiratory muscle function in patients with different severity of OSA. Participants firstly
      underwent polysomnography assessments will be recruited. The measurements includes Epworth
      sleepiness scale, strength and endurance of inspiratory muscles, and fatigue test during
      either maximal voluntary efforts or in response to cervical magnetic stimulation (CMS) with
      simultaneously sEMG recordings. In addition, the exercise capacity with simultaneous sEMG
      recordings for diaphragm and vastus lateralis during the exercise testing will also be
      tested. The second part is designed to examine the metabolic characteristics of lower
      extremity in patients with OSA. Blood samples will be drawn and proton magnetic resonance
      spectroscopy is used to detect intramyocellular and extramyocellular lipid contents (IMCL and
      EMCL). The third part will detect the effect of exercise training on the measured parameters
      described as above in patients with OSA. Participants will be randomized into exercise group,
      inspiratory muscle training group (IMT), and CPAP group. Exercise protocol includes 30-minute
      aerobic exercise at the intensity of 70%-85% VO2max, and 20-minute general resistance
      exercise. IMT group will receive inspiratory muscle strengthening by device.
    

Intervention name(s): exercise training, IMT
Intervention type(s): Behavioral
Intervention description(s): Each exercise session includes graded treadmill walking and resisted exercises. The graded treadmill walking exercise begins with a 5 minute warm-up period with the intensity of about 40% of maximal oxygen consumption (VO2max) follows by a 30 minutes training phase. The training intensity is set at about 70%-85% of VO2max and ends with a 5-minute cool-down period with the intensity of about 40% of VO2max. The resisted exercise program includes 20 minutes of weight training with rest after the first 5 minutes.
Other intervention name(s): exercise
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: obstructive sleep apnea; skeletal muscle; magnetic stimulation; magnetic resonance spectroscopy; inflammatory markers; exercise