Effect of Positive Airway Pressure on Reducing Airway Reactivity in Patients With Asthma (CPAP)

Inclusion criteria * 15 - 60 years of age at V1 * Physician diagnosis of asthma and on prescribed asthma medication for at least the past 12 months at V1 * Pre-bronchodilator FEV₁ greater than or equal to 75% predicted at V1 (to minimize the likelihood that variability in FEV₁ will preclude participants from having methacholine challenges in follow-up visits) * Airways reactivity: Methacholine bronchial challenge with concentration of methacholine causing a 20% fall in forced expiratory volume in 1 second (PC ₂₀) less than or equal to 8 mg/mL at V1 * Stable asthma defined by no change in treatment, emergency department (ED) visit, hospitalization, or urgent health care visit for asthma for the 8 weeks prior to screening * Non-smoker for more than 6 months and less than or equal to 10 pack-year history of smoking * Ability and willingness to provide informed consent * If receiving immunotherapy, must have had stable therapy for the 8 weeks prior to screening * Spend a minimum of six hours per night in bed on average * Willingness to sleep 5 days a week on average in the same place for the next 4 months * For women of child bearing potential; not pregnant, not lactating and agree to practice and adequate birth control method (abstinence, combination barrier and spermicide, or hormonal) for the duration of the study Exclusion criteria * Weight less than or equal to 66 lbs. (30kg) at V1 * BMI greater than or equal to 35 at V1 * Acute respiratory illness in the month prior to s…