During the overnight sleep study, the sleep technician will count the number of times you stop breathing or demonstrate shallow breathing during your sleep. If that number is five events per hour or more, you may have sleep apnea. If you demonstrate moderate to severe sleep apnea during the initial part of the study, the technician will come into your room and start nasal Continuous Positive Airway Pressure (CPAP) therapy. During the remaining portion of the study, the technician will adjust the air pressure setting on the CPAP until the sleep apnea is treated.