Increased Lung Volume as Controller Therapy for Asthma

This is an early phase clinical trial to test the efficacy of elevating lung volume with positive expiratory pressure (CPAP) as a controller therapy for asthma in patients with a BMI ≥ 30 kg/m2. There will be two phases to this trial. Phase I: In the first phase we will determine the optimal duration of CPAP that is effective as a controller therapy in asthma. Up to 9 participants will complete this this phase. Phase II: The 2nd phase will be a randomized double-blinded controlled trial of Sham CPAP versus CPAP 10 (using the duration of CPAP determined in phase I) as a controller therapy for asthma, and also to determine the effect o airway reactivity in healthy people with a BMI 30 kg/m2 and above. Twenty people with asthma and twenty controls will complete this phase.