Effect of CPAP (Continuous Positive Airway Pressure) on Lung Function in Asthmatics With Sleep Apnea

Inclusion Criteria: * Adult (\>18yrs at the time of recruitment) * Body mass index (BMI) ≥ 30 * Symptoms suggestive of sleep apnea * Epworth Sleepiness Score (ESS) within range * Positive sleep study for sleep apnea Exclusion Criteria: * Tobacco use within the last 3 months. * Presence of other significant comorbid heart or lung disease * Presence of another chronic inflammatory disease, such as connective-tissue disease, inflammatory bowel disease, or active infection. * Use of systemic steroids, as defined as any prednisone use in the preceding 3 months. * Use of leukotriene antagonists or theophylline within the preceding 6 weeks. * Presence of severe or uncontrolled sinusitis, such that CPAP therapy will be difficult or uncomfortable. * History of significant claustrophobia, uncontrolled psychiatric disease, or anticipated intolerance of CPAP therapy. * Night shift workers, or other subjects with significantly altered sleep-wake cycles. * Baseline post-bronchodilator FEV1 \< 70% predicted. * Severe gastroesophageal reflux disease.