Effect of CPAP on Breath Hold and Chest Movement in Normal Volunteers

Inclusion Criteria: * Normal volunteers without a cancer diagnosis. * No contraindications to the use of CPAP * Facial injury or deformity preventing wearing facial mask * Recurrent vomiting * Chronic cough with phlegm * Previous pneumothorax * Facial lacerations or fractures * Recent tracheal or esophageal anastomosis * Recent GI surgery (last 90 days). * 18-90 years of age * Ability to sign informed consent * Hebrew or English speakers Exclusion Criteria: * Contraindications to CPAP * Facial injury or deformity preventing wearing facial mask * Recurrent vomiting * Chronic cough with phlegm * Previous pneumothorax * Facial lacerations or fractures * Recent tracheal or esophageal anastomosis * Recent GI surgery (last 90 days). * Under age 18 or above age 90 years * Inability to sign informed consent * Members of special populations (mental illness, pregnant women, prisoners, not legally competent). * History of severe active restrictive or obstructive lung disease (as defined as at least one hospitalization over previous two years) * Any medical condition requiring an inpatient hospitalization for more than 72 hours over the previous 2 years, aside from elective surgery.