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Sleep · product guide

CPAP Machines & Accessories: does it work?

CPAP is first-line treatment for obstructive sleep apnea. It is a prescription medical device: get tested first, then mask fit and nightly use decide whether it works.

Strong evidenceReviewed September 2026

What it is

CPAP (continuous positive airway pressure) blows air through a mask at a set pressure that holds your throat open during sleep. Auto-adjusting machines vary the pressure within a prescribed range; bilevel machines use separate pressures for breathing in and out, for people who need higher pressures or have other breathing problems. Heated humidifiers and heated tubing reduce dryness and congestion. Masks come as nasal pillows (small cushions at the nostrils), nasal masks, and full-face masks for mouth breathers. This shelf also includes travel machines, CPAP pillows and cleaners.

Obstructive sleep apnea is common and often missed. Warning signs: loud, regular snoring; breathing pauses, choking or gasping that someone notices; daytime sleepiness or dozing while driving; morning headaches; waking to pass urine; and high blood pressure that's hard to control. Diagnosis needs a sleep study, often done at home, and in the US the machine and mask need a prescription.

How strong is the evidence?

Strong evidence

PAP removes most breathing events, and randomized trials show it reduces daytime sleepiness and improves quality of life and mood; the American Academy of Sleep Medicine strongly recommends it for adults with obstructive sleep apnea and excessive sleepiness. It lowers blood pressure modestly (about 2-3 mmHg on average, more with more hours of use). In the large SAVE trial it didn't prevent heart attacks or strokes in people with existing heart disease, but average use was only 3.3 hours a night, and pooled data link 4+ hours a night with fewer repeat events.

The claims you'll see, checked

CPAP reduces daytime sleepiness

Holds up

Consistent in randomized trials; it's the main reason guidelines strongly recommend it.

CPAP lowers blood pressure

Holds up

Pooled trials show about 2.5/2.0 mmHg lower, with more benefit for each extra hour of nightly use.

CPAP prevents heart attacks and strokes

Mixed

The largest trial found no reduction in people with heart disease. People who used it 4+ hours a night did better in pooled analyses, but that can partly reflect healthier habits.

CPAP makes driving safer

Holds up

Observational studies of drivers with apnea show crash risk falls sharply after treatment, and sleepiness improves within days.

You can choose a machine yourself without a sleep test

False

Pressure needs and even the right type of machine depend on the diagnosis. Central sleep apnea and some heart and lung conditions need different settings or devices.

Ozone or UV cleaners are needed to keep CPAP safe

False

Mild soap and water, following the maker's instructions, is enough. The FDA has warned about ozone and UV cleaners that weren't authorised for this use.

What to look for

  • A mask that fits your face and sleep style: nasal pillows for minimal contact, full-face if you breathe through your mouth. Most people try more than one, and fit drives whether you'll keep using it.
  • A heated humidifier, and heated tubing, if you get a dry mouth, nosebleeds or condensation in the mask.
  • Comfort settings: a ramp that starts at low pressure, and pressure relief when you breathe out.
  • Usage data your clinician can see (hours of use, mask leak, remaining events). Insurers often require proof of use.
  • A travel unit if you fly often, with battery options and approval for in-flight use.
  • For any second-hand or older machine: have your provider check and set it, and look it up in the FDA recall database. A large 2021 recall covered millions of machines with degrading sound-dampening foam.

What to skip

  • Ozone 'sanitisers'. Soap and water does the job, and ozone irritates the lungs.
  • Buying a machine online without a diagnosis and a prescribed pressure setting.
  • Upgrading for app features or special algorithms when your current setup works. Ask your clinician whether it would change anything.

How to use it

  • Use it all night, every night. At least 4 hours on 70% of nights is the threshold many US insurers use to judge adherence, but more hours bring more benefit.
  • Get used to the mask while awake, for example wearing it while reading or watching TV.
  • Use the ramp setting so the pressure starts low as you fall asleep.
  • Wash the cushion and tubing with mild soap as your supplier advises, and use distilled water in the humidifier.
  • Bring your usage data to follow-up visits; leak and remaining events show whether settings need changing.

Who should be careful

  • Don't self-prescribe. Central sleep apnea, heart failure, lung disease and other conditions change which device and settings are safe.
  • Tell your prescriber about recent facial, sinus, ear or skull-base surgery, a history of collapsed lung, or severe lung disease.
  • If you have untreated apnea and daytime sleepiness, don't drive when drowsy.
  • Tell your care team early about dryness, leaks, pressure discomfort or claustrophobia. Most problems are fixable, and quietly giving up is the commonest way treatment fails.
  • Clean the mask and tubing, and replace cushions, filters and tubing on the schedule your supplier gives.
  • If CPAP really doesn't work for you, alternatives include oral appliances, positional therapy, weight loss (including medicines) and, for some people, surgery or nerve stimulation.

The studies

Every citation is checked against its PubMed record.

  1. Treatment of Adult Obstructive Sleep Apnea with Positive Airway Pressure: An American Academy of Sleep Medicine Clinical Practice Guideline
    Patil SP, Ayappa IA, Caples SM, Kimoff RJ, Patel SR, Harrod CG · Journal of Clinical Sleep Medicine · 2019 · Guideline

    Strongly recommends PAP for adults with obstructive sleep apnea and excessive sleepiness, suggests it for impaired quality of life and comorbid hypertension, and requires diagnosis by objective testing plus follow-up of usage data.

  2. CPAP for Prevention of Cardiovascular Events in Obstructive Sleep Apnea
    McEvoy RD, Antic NA, Heeley E, Luo Y, Ou Q, Zhang X, et al. · New England Journal of Medicine · 2016 · RCT

    2,717 adults with moderate-to-severe sleep apnea and heart or brain vascular disease. With average use of 3.3 hours a night, CPAP did not reduce cardiovascular events over 3.7 years, but it reduced snoring and sleepiness and improved quality of life and mood.

  3. CPAP vs Mandibular Advancement Devices and Blood Pressure in Patients With Obstructive Sleep Apnea: A Systematic Review and Meta-analysis
    Bratton DJ, Gaisl T, Wons AM, Kohler M · JAMA · 2015 · Network meta-analysis

    51 trials (4,888 patients). CPAP lowered blood pressure by about 2.5/2.0 mmHg versus inactive control, with about 1.5 mmHg more systolic reduction per extra hour of nightly use; oral appliances gave similar reductions.

  4. Adherence to CPAP Treatment and the Risk of Recurrent Cardiovascular Events: A Meta-Analysis
    Sánchez-de-la-Torre M, Gracia-Lavedan E, Benitez ID, Sánchez-de-la-Torre A, Moncusí-Moix A, Torres G, et al. · JAMA · 2023 · Individual participant data meta-analysis

    4,186 people with heart disease and sleep apnea from three RCTs. Overall CPAP did not change recurrent cardiovascular events (HR 1.01), but in an on-treatment analysis good adherence (4+ hours a night) was linked with lower risk (HR 0.69).