CPAP, or continuous positive airway pressure, devices are commonly used by people with obstructive sleep apnea, a serious condition that affects 12 million Americans. It causes people to stop breathing many times a night as the soft tissues in the throat collapse and close up, blocking the airway.

Untreated sleep apnea can cause high blood pressure, heart attacks, and stroke, according to the National Heart Lung and Blood Institute. Poor sleep also leads to daytime drowsiness, which impairs job performance and increases the risk of traffic accidents.

Using a CPAP machine, which involves wearing a mask over the face and breathing through a tube that pushes in air at a pre-determined pressure, allows a person to stay asleep all night – instead of waking up repeatedly gasping for air. They also reduce snoring, a big plus for the spouse.

But a significant portion of CPAP users – 50 percent, by some estimates – give up on the machines because of side effects, which can include a dry or stuffy nose, irritated skin on the face and discomfort.

Claustrophia is also a common problem, says Dr. Kenneth Sassower, a sleep neurologist at Massachusetts General Hospital. So is distress triggered by the fact that air is pumped in as the person exhales, making it slightly more difficult to exhale, says Dr. Geoffrey Gilmartin, director of the Sleep Disorders Center at Beth Israel Deaconess Medical Center. Trouble exhaling can lead to swallowing air and stomach bloating.

But there are ways to adjust to a CPAP machine, such as working closely with sleep lab experts until you get a mask that fits and getting the device’s air pressure set properly, says Dr. Aaron Waxman, director of the pulmonary vascular disease program at Massachusetts General Hospital.

It can also help to have the air pressure ramp up gradually so you can adjust to it as you’re trying to fall asleep. If you can’t adjust to the CPAP machine, a dental appliance like a retainer that thrusts the lower jaw forward may help keep the throat open.