Consumer Reports offers a guide to finding the right CPAP machine for those struggling with this sometimes challenging therapy for sleep apnea.

A gradual introduction to CPAP works best for many people. Start by using your CPAP for 20 to 30 minutes before bed.

If you find that the mask that felt right during your fitting is uncomfortable after a few nights, or that it’s difficult to adjust, contact your sleep medicine doctor or the medical equipment provider. You may need advice on adjusting or a different style of mask.

If you wear a full mask, have your sleep medicine specialist or sleep technician check its fit. For mouth-breathing, ask whether a chin strap can be added to your nasal mask or nasal pillow devices to hold your mouth shut during sleep.

Most newer CPAP machines come with a built-in humidifier—you can adjust the level of humidification so that it might ease nasal congestion. If that doesn’t help, talk to your doctor.