The best CPAP pillows for side sleepers

For most people with obstructive sleep apnea (OSA), the airway collapses more easily on the back than on the side. OSA is common: a ResMed-funded modelling study estimated that 936 million adults aged 30 to 69 have it worldwide^[1]. In a sleep clinic series of 574 patients, 55.9% had positional OSA, meaning at least twice as many breathing events on the back as on the side. People with severe OSA were less likely to be positional^[2]. A community sample of 1,870 adults with OSA put the positional share at 62%^[3].

The reason is mostly mechanical. On your back, the airway blocks more often, especially at the soft palate and the epiglottis, and it is reliably more collapsible than when you lie on your side^[6]. In a small lab study of eight people with severe OSA, lying on the side roughly halved the pressure needed to reopen the airway, from 10.4 to 5.5 cm H₂O^[7]. Pressure needs also shift with position, alcohol and weight, the main case for auto-adjusting machines^[8].

Side sleeping doesn't replace CPAP

Positional therapy helps some people, but CPAP does more. A 2019 Cochrane review of eight trials (323 people) found that devices keeping people off their backs cut the apnea-hypopnea index (AHI) by about 7 events an hour compared with a sham or no treatment. In the trials that compared the two directly, CPAP cut it by 6.4 more events an hour than positional therapy (short trials, low-certainty evidence)^[9]. Only some people breathe normally on their side: in the community study, 513 of the 1,870 people with OSA (about 27%) had supine-isolated OSA, with at least twice as many events on the back and a normal AHI (under 5) off it^[3]. A 2006 AASM practice parameter lists positional therapy as a secondary or add-on treatment for people whose AHI is low off their back, and says the benefit should be confirmed with a sleep test, because not everyone normalizes^[10].

CPAP only helps during the hours you wear it, and many people struggle to wear it enough. Medicare's coverage rules define adherence as at least 4 hours a night on 70% of nights in a 30-day stretch during the first three months^[11]. Older studies using a 4-hour cutoff found that 46% to 83% of patients fell short, while use of more than 6 hours a night was linked to less sleepiness and better daily function^[12]. Newer machine data look better: in a ResMed-funded analysis of 2.6 million patients, 75% met the Medicare definition within 90 days^[13]. That still leaves one in four.

Side effects drive much of the drop-off. Up to 25% of patients stop CPAP because of them, and unintentional mask leak is the most reported^[4]. Timing matters too: the decision to stick with CPAP tends to be made in the first few days of treatment^[12]. If lying on your side pushes your mask off, fix it in week one, not month three.

On your side, the pillow presses on the mask and headgear, and every turn can break the seal. One study analyzed leaks in 10-second slices across 74 overnight sleep studies of people on auto-CPAP. Four things independently raised the risk of leak: mouth opening, higher pressure, REM sleep, and lying in any position other than on the back^[14]. The authors didn't study pillows; our reading is that a pillow pushing the cushion sideways is a likely cause. Bulky masks fare worst: ResMed's advice for side sleepers warns that larger masks can be uncomfortable when pressed against a pillow^[15].

You also move more than you think. An accelerometer study of 664 adults recorded about 1.6 position changes an hour^[16], so a seal that holds at lights-out gets tested many times a night. Among 1,484 long-term CPAP users, leak was the most common mask complaint (75.4% of those who answered), and reported leaks were linked to leftover daytime sleepiness. What people noticed didn't match the leak figures their machines recorded^[17], so a clean machine report doesn't rule out a leak problem.

Cutouts along the pillow's edges give your mask somewhere to go when you lie on your side, so it isn't pushed into your face, breaking the seal or leaving red marks. Most CPAP pillows also have a removable layer to set the height and a channel or corner cutout for the hose.

The evidence is thin. The only controlled trial we found gave 22 people new to auto-CPAP five nights on their own pillow, then five nights each on a foam and a gel pillow with side cutouts, in random order. Leak, pressure, residual AHI and hours of use didn't differ between the three pillows, but people preferred the gel pillow^[5]. Each pillow got only five nights, a gel-pillow maker helped fund the study, and all but one participant wore a nasal mask. On average, participants already used CPAP for more than 6 hours a night on every pillow, which left little room to improve.

Our take: buy a CPAP pillow for comfort, not as a proven leak fix.

The smaller your mask, the less your pillow matters. CPAP masks come in four main styles^[18]:

• Nasal pillows seal at the nostrils and touch the least skin. A soft pillow pushed away from the face is often enough.
• Nasal masks cover the nose. Cleveland Clinic notes that providers often recommend them if you move around a lot in your sleep. Shallow side cutouts are usually enough.
• Full-face masks cover the nose and mouth and suit people who breathe through the mouth or have a blocked nose. They stick out furthest, so they gain most from deep corner cutouts like the EnduriMed's.
• Hybrid masks cover the mouth and seal at the nostrils without covering the bridge of the nose. Treat them like a smaller full-face mask.

Don't move to a bigger mask just to cope with your pillow. A meta-analysis of 13 studies (4,563 patients) linked full-face masks with about 1.5 cm H₂O more pressure, 2.8 more residual breathing events an hour and 48 fewer minutes of use a night than nasal masks^[19]. Most weren't randomized, so mask choice may reflect other differences. The AASM still advises clinicians to generally choose nasal or intranasal masks over full-face ones^[8]. Nasal pillows and nasal masks perform about the same on pressure and residual AHI^[20]. If you want to change mask type, ask your sleep clinician or equipment supplier to fit it.

Set the pillow for your mask first, then fit the mask to you lying on your side. For general loft targets, see how to choose a pillow.

1. Set the height. Add or remove layers until the mask sits inside the cutout, not on the pillow surface, with your nose roughly in line with the middle of your chest. The Lunderg's removable 1.1-inch layer and the CPAPMax's layers make this easy.
2. Wash, then fit lying down. NHLBI advises cleaning your mask and washing your face before putting it on, which helps the seal, and adjusting the mask every night while lying down with the machine on^[21].
3. Loosen, don't crank. ResMed suggests a looser fit that still seals, and giving it at least two or three nights^[22].
4. Reseat after turning. If the mask leaks after you roll over, try ResMed's fix for leaks around the face: gently pull the cushion away from your face so it can reinflate^[23].

Bring the hose in from above, not across the pillow. A hose that hangs off the nightstand tugs on the mask every time you turn. Route it over the headboard or use a hose hanger so it drops from above. Masks with the tube connecting at the top of the head work the same way: ResMed says tube-up designs help the mask stay in place without the hose getting in your way^[15]. A swivel elbow at the mask helps when you roll, and four-corner cutouts (EnduriMed) reduce tangling when you switch sides.

If you wake to gurgling or water in the mask, that's “rainout”: condensation that forms when the air in the hose is warmer than your room. ResMed's fixes are heated tubing, a tubing wrap (or the hose under your covers), a warmer bedroom, or a lower humidifier setting^[24].

Dry mouth matters more than it sounds: it's the mask side effect linked to skipping CPAP. In the 1,484-person long-term study, it was the mask side effect the authors found independently linked to using CPAP less than 4 hours a day^[17]. Cold, dry air is the usual cause^[18], and mouth leak adds to it. Mouth opening and positions off the back both raise leak risk^[14].

• Humidification: the AASM advises clinicians to generally use heated humidification to reduce side effects^[8]. NHLBI says your provider may suggest a humidifier or nasal spray for dry mouth or a stuffy nose^[21].
• Chin straps: in a small study of 15 people with mouth leak on nasal CPAP, a chin strap cut mouth leak from 42.9% to 23.8% of sleep time. But snoring rose, mouth leak stayed higher than the authors considered acceptable, and they warn a chin strap can, in rare cases, worsen breathing^[25]. Ask your clinician before relying on one.
• Full-face masks: in the leak study, full-face masks lowered the risk of leak during mouth opening and REM sleep^[14]. That's a case for one if you breathe through your mouth, despite the adherence trade-offs above.

Red marks usually mean the mask is too tight, the wrong size, or being pushed into your face. In the long-term study, 9.6% of women and 5.3% of men rated mask injury at 5 or more on a 0-to-10 scale^[26]. Cleveland Clinic says the right mask size and padding minimize irritation^[18]. ResMed adds checking for stretched headgear or a worn cushion, keeping the mask clean, adding a pad between cushion and skin, and, if you own both a nasal and a nasal pillows mask, alternating them to rest different spots^[22]. For side sleepers, the cutout does part of the job: if the pillow isn't pushing the cushion into your cheek, you don't need tight straps to hold the seal. Broken skin or sores that keep coming back need a refit from your supplier.

Use mild soap and water, and skip ozone and UV gadgets. The FDA says most CPAP accessories, including hoses and masks, can be cleaned with mild soap and water, following your manufacturer's instructions. It has received reports of asthma attacks, headaches and breathlessness after ozone cleaners, warns that ozone inside the equipment can stay above safe limits for hours after cleaning, and notes that both UV light and ozone can break down hoses and masks^[27]. Cleveland Clinic advises cleaning the mask and tube every day^[18].

Call your clinic or supplier if leaks, discomfort or symptoms persist, rather than changing settings yourself. The AASM says follow-up should include troubleshooting and checking your machine's usage and efficacy data, partly because patients often overestimate how much they use CPAP^[8]. Machines track hours of use reliably. Leak and residual-event figures are harder to read, because each manufacturer defines them differently, so very high or very low values are the ones that count^[28]. NHLBI lists these reasons to talk to your provider^[21]:

• Your mask doesn't stay on or fit well, or it leaks air.
• You have dry mouth or a stuffy or runny nose.
• You have trouble falling or staying asleep.
• You feel claustrophobic or the noise bothers you.

NHLBI also notes you may need a repeat sleep study if you gain or lose a lot of weight. A pillow can make the setup more comfortable, but it can't tell you whether treatment is working.

Not always. With a nasal pillows mask and a soft, moldable pillow, maybe not. Many people do fine with an adjustable shredded pillow pushed away from the mask (see Coop). With a nasal or full-face mask, cutouts give the mask room and are more likely to help. If you spend part of the night on your back, see our side and back sleeper guide, and if you run hot, compare options in our cooling pillow guide.