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Do an overnight sleep study. Consult with your doctor. Ask your doctor about an auto-adjusting CPAP.
When you sleep overnight in a specialized sleep laboratory and get diagnosed with sleep apnea, the team of doctors will determine what the optimum average constant pressure is for you on your CPAP machine. The process by which they figure out the most appropriate air pressure is called a titration study. A titration study is done with a mask and air machine for the purposes of calibrating a CPAP machine to a level that stops your sleep apnea events.  The events are measured in a point system called an apnea hypopnea index. An index below five indicates no sleep apnea.  Mild OSA: AHI of 5-15. Involuntary sleepiness during activities that require little attention, such as watching TV or reading Moderate OSA: AHI of 15-30. Involuntary sleepiness during activities that require some attention, such as meetings or presentations. Severe OSA: AHI of more than 30. Involuntary sleepiness during activities that require more active attention, such as talking or driving.    Sleep clinics typically do not recommend that new CPAP users change their pressure settings until they've had their first sleep study and used the prescribed pressure settings for several weeks at minimum. While you are in the sleep lab, the doctor or sleep specialist may also: Measure your activity levels and movement as you sleep Record your brain activity, eye movements, blood pressure, heart rate, and blood oxygen levels Fine-tune the fit of your mask and the air pressure settings Doctors and manufacturers recommend that the air pressure settings of your CPAP machine be personalized for you by a medical professional based upon a titration study at a sleep clinic — you should then use those recommended settings for at least a few weeks to get used to them at night. If you think those initial settings need to be adjusted, you should contact your doctor or sleep clinic to have them checked. Adjustment of the air pressure settings may be necessary when:  You gain or lose weight You are extra tired You have had a few alcoholic drinks You are on prescribed sedatives You have sinus congestion You are using a different mask You are at a different altitude You have jet lag You change stages in your sleep cycle If you're considering changing your CPAP air pressure settings, the safer method is to upgrade from a constant-pressure machine to an auto-CPAP machine. These fully automated machines continually measure the air pressure needed to keep your airways open and then self-adjust on a regular basis according to your ongoing needs.  An auto-CPAP machine is likely the best long-term option, since your air pressure needs change day by day (and even hour by hour) as you sleep. A one-time titration study within a sleep clinic cannot account for various personal changes that impact air pressure needs, such as: what sleep stage you're in, sleeping position, what you eat / drink, your body weight, and various drugs you take. Auto-adjusting helps prevent you from swallowing air at times when your standard pressure is too high. Swallowing air can make people feel bloated and disrupt their sleep.