Do you feel tired during the day? Are you possibly overweight? Do people tell you you snore?  Then you need to consider the possibility that you have sleep apnea. If you have sleep apnea, the doctors at the sleep center will write a prescription for treatment, which might include a weight loss program. If the apnea is severe, the doctors will probably prescribe a sleep apnea machine such as a CPAP.

If you avoid treatment, your life will be shortened—sleep apnea causes blood pressure spikes during held breath, and leads to increased risk of stroke and heart attack. You’re deprived of oxygen, and your mental functioning may suffer.  In addition, the quality of your life will remain under par—you’re sleepy all the time.  So it’s time for you to find out all about these machines. Once you get one, plan to use it every night, even when traveling.

The CPAP is a small electric blower that pushes air into a hose.  The hose is attached to a mask, held on by straps.  The hose supplies enough air pressure (as determined by the sleep center) to keep your airway from collapsing as you sleep.

The doctor probably won’t prescribe the exact model of CPAP machine. Your insurance company will probably steer you toward a few models.  But hopefully you will have some leeway to pick features:

Sleep Apnea Mask

The mask is the single most important feature.  Get it right, or you may be tempted to back out of the treatment plan later. The mask needs to fit you well.  Sleep apnea sufferers are told to sleep on their sides.  But sideways pressure from your pillow may cause your mask to slip and let air leak out.  Users report that this is a noisy event, particularly annoying to your bed partner.  It is important that you spend some time trying on masks and pushing on them from the side, to imitate the sideways force that would come from your pillow as you move your head around in sleep. More mask tips:  go for smaller, not larger, because larger masks are more likely to leak. Like to read yourself to sleep?  Be sure to choose a mask that’s low over the bridge of the nose. Like to breathe through your mouth? There’s a mask that delivers the air to your mouth, not your nose. Here’s a tip: buy two masks of different types and alternate them, so your skin doesn’t get chafed too much.

Bi-level pressure

The pressure can be continuous, as in older models, or bi-level. With bi-level, the pressure is lower when you exhale.  This feature is also called C-Flex.  Without it, you may be laboring to exhale.

Pressure ramping up slowly. Many models increase pressure every five minutes for 30 minutes, until the full pressure is reached.  This gives your body a chance to adjust gradually to the machine.  Some have a ramping control that you can adjust.

Integrated heated humidifier, to keep your airway from drying out. Some manufacturers say their models inhibit condensation from forming inside the tube and mask.

Battery pack. You should ask whether it contains enough power to get you through eight hours of sleeping on an airplane, with the humidifier/heater on.  For most models, the heater will bring the time down below what you'd like.

Altitude adjustment, automatic or manual. Will you be traveling to high places? Flying in airplanes?  Some models have an automatic altitude adjustment. Others are manual. Some go to 7,800 feet or 11,000 feet.  Do they work in an airplane at 40,000 feet? You need to ask that.

Data storage. Many units capture data that can be sent to your sleep center. he data includes recording any apneas, and monitoring whether you are getting enough sound sleep. The doctor can use the data to make pressure adjustments. How much data can be stored--one night or nine months?  That's the range available.  How do you send the data? Some use a data card; others hook to your PC.  Figure out a method that works for you.

DC or direct current adapters, to hook to your car battery if you are camping.

AC adjustment, so you can use it in America (120 V) or Europe (240 V).

Hose length. The standard hose length is six feet. Hoses longer than 12 feet won’t maintain the pressure from the machine, and will require increased pressure. To avoid getting tangled in the hose as you sleep, you can plan to drape the hose over the headboard of your bed, or over an object (such as a chair) that you set up for that purpose.