Getting a sleep apnea diagnosis can feel like a lot to take in at once. One day you’re filling out a questionnaire about snoring and daytime tiredness, and the next you’re staring at a report full of unfamiliar terms, wondering whether you need a CPAP machine, a BiPAP machine, or something else entirely. If that’s where you are, take a breath — this guide walks through the basics in plain language, so your next conversation with your doctor (or with us) feels less like a foreign language.
Table of Contents
- What Is Obstructive Sleep Apnea?
- Understanding Your Sleep Study and AHI Score
- How a CPAP Machine Works
- How a BiPAP Machine Works
- CPAP vs BiPAP: At a Glance
- Who Usually Gets Prescribed CPAP First
- Who Typically Moves to BiPAP
- Common Concerns Beginners Have
- Mask Discomfort
- Aerophagia (Swallowing Air)
- Getting Used to the Machine Itself
- Buying vs Renting: A “Let’s Try This First” Mindset
- What to Expect in Your First Week of Therapy
- Frequently Asked Questions
What Is Obstructive Sleep Apnea?
Obstructive sleep apnea (OSA) happens when the soft tissue at the back of your throat relaxes during sleep and partially or fully blocks your airway. Your brain notices the drop in oxygen, briefly wakes you (often without you realizing it), and your airway reopens — sometimes with a snort or gasp. This can happen dozens or even hundreds of times a night, which is why people with untreated OSA often wake up exhausted no matter how many hours they slept.
Common signs include loud, chronic snoring, gasping or choking during sleep, morning headaches, and feeling drained despite a full night in bed. A partner often notices the breathing pauses before the person with apnea does. If this sounds familiar and you haven’t been formally evaluated yet, our STOP-BANG screening questionnaire is a quick way to gauge your risk before booking a sleep study, and our sleep apnea overview page covers the condition in more depth.
Understanding Your Sleep Study and AHI Score
Diagnosis usually comes from a sleep study, either an overnight stay at a sleep lab (polysomnography) or a simpler home sleep apnea test. Both track your breathing, oxygen levels, and body movements while you sleep, and the results are used to calculate your Apnea-Hypopnea Index, or AHI — the average number of apneas (complete pauses in breathing) and hypopneas (partial blockages with shallow breathing) you experience per hour of sleep.
Your AHI score is what your doctor uses to classify severity and decide which sleep apnea machine and settings make sense for you. Here’s the standard adult classification:
| AHI (events per hour) | Severity | What it generally means |
|---|---|---|
| Fewer than 5 | Normal | No clinically significant sleep apnea |
| 5 to 15 | Mild | Occasional breathing interruptions; lifestyle changes or therapy may be discussed |
| 15 to 30 | Moderate | Frequent enough to disrupt sleep quality most nights; treatment is usually recommended |
| More than 30 | Severe | Breathing is interrupted many times an hour; treatment is strongly recommended |
It’s worth remembering that the AHI number is only part of the picture. Your doctor will also factor in your oxygen levels during sleep, your symptoms, and any other health conditions — like heart disease, high blood pressure, or lung conditions — before recommending a CPAP machine, a BiPAP machine, or further testing.
How a CPAP Machine Works
CPAP stands for Continuous Positive Airway Pressure. A CPAP machine pushes a steady, constant stream of pressurized air through a hose and mask into your airway, which acts like a splint to keep your throat from collapsing while you sleep. The key word is “continuous” — the pressure stays the same whether you’re breathing in or breathing out.
For most people with obstructive sleep apnea, this single steady pressure is enough to keep the airway open and eliminate the pauses in breathing. It’s a simpler mechanism than BiPAP, which is one reason a standard CPAP machine is typically the first therapy your sleep doctor will suggest.
How a BiPAP Machine Works
BiPAP stands for Bilevel Positive Airway Pressure (sometimes called BPAP). Instead of one constant pressure, a BiPAP machine delivers two different pressure levels — a higher pressure when you breathe in (called IPAP, or inspiratory positive airway pressure) and a lower pressure when you breathe out (EPAP, or expiratory positive airway pressure).
Why does that difference matter for comfort? Breathing out against strong, constant pressure — the way a CPAP machine works — can feel effortful for some people, almost like exhaling into the wind. Because a BiPAP machine automatically eases the pressure during exhalation, it can feel more natural to breathe with, especially for people who need higher pressure settings to keep their airway open. This is why a BiPAP machine is often introduced when a straightforward CPAP setup isn’t quite doing the job.
CPAP vs BiPAP: At a Glance
This isn’t a full spec comparison — it’s meant to give a beginner a quick sense of how the two therapies differ in everyday, practical terms.
| Feature | CPAP Machine | BiPAP Machine |
|---|---|---|
| Pressure delivery | One constant pressure, inhale and exhale | Two pressures — higher on inhale, lower on exhale |
| Typical first choice for | Newly diagnosed, uncomplicated obstructive sleep apnea | Those who need higher pressure or find CPAP hard to exhale against |
| Mechanism complexity | Simpler, single-pressure design | More adjustable, dual-pressure design |
| Common candidates | Mild-to-moderate OSA | Higher-pressure needs, certain complex or central breathing conditions |
| Learning curve | Generally quick to adapt to | May take slightly longer to settle into due to pressure switching |
If you’d like a deeper, spec-by-spec breakdown of specific ResMed CPAP and BiPAP models, that’s covered in detail elsewhere on our blog — this guide is focused purely on helping you understand which category of sleep apnea machine fits your situation.
Who Usually Gets Prescribed CPAP First
For most newly diagnosed adults with obstructive sleep apnea — particularly mild to moderate cases — a standard CPAP machine is the first line of treatment recommended by sleep specialists. It’s effective, well-studied, and simpler to use than a bilevel device, which makes it a sensible starting point for beginners who have never used positive airway pressure therapy before.
If this is your first machine, there’s no shame in starting simple. Many people do perfectly well on CPAP for the entirety of their therapy and never need to switch.
Who Typically Moves to BiPAP
A BiPAP machine tends to enter the conversation in a few specific situations:
- CPAP pressure isn’t enough. Some people need higher pressure settings than a standard CPAP machine can comfortably deliver, and BiPAP machines generally support a wider range.
- Exhaling against pressure feels difficult. If breathing out against constant CPAP pressure feels like a struggle, BiPAP’s dual-pressure design can be easier to tolerate.
- CPAP alone hasn’t resolved symptoms. If a follow-up sleep study shows CPAP isn’t fully controlling the breathing interruptions, your doctor may suggest switching.
- More complex breathing patterns are involved. Conditions affecting breathing control, or a mix of obstructive and central sleep apnea, are often treated with bilevel therapy instead.
None of this is something you need to figure out alone — it’s a decision made with your sleep physician, based on your sleep study results and how you respond to initial treatment.
Common Concerns Beginners Have
It’s completely normal to feel a little apprehensive before your first night with a mask and hose. Here are the concerns we hear most often from first-time users, and what tends to help.
Mask Discomfort
A mask that doesn’t fit well is, by far, the most common reason people struggle in the early days. Too tight, and it leaves marks and pressure points; too loose, and air leaks disrupt the seal and your sleep. The good news is that masks come in several styles — nasal pillows, nasal masks, and full-face masks — and finding the right one is mostly a matter of matching the style to how you breathe. Our mask fitting guide walks through how to pick between them, and browsing our CPAP mask range side by side helps you see the options.
Aerophagia (Swallowing Air)
Aerophagia is what happens when pressurized air ends up in your stomach instead of your lungs, leading to bloating, burping, or gassiness. It’s a fairly common early side effect, often linked to mouth leaks or a pressure setting that feels higher than your body is used to. For most people it eases as they adjust, and it can often be improved by refitting the mask, addressing mouth breathing, or having your clinician review your pressure settings. If exhaling against pressure seems to be the trigger, this is one of the specific situations where a BiPAP machine is sometimes considered instead.
Getting Used to the Machine Itself
Sleeping with a mask strapped to your face and a hose attached to it is, understandably, a strange sensation at first. Some people feel a flicker of claustrophobia the first few nights — a normal reaction that typically fades with patience and consistency. Wearing the mask for short stretches while awake, reading or watching TV, can help your brain get used to the sensation without the added pressure of also trying to fall asleep.
Buying vs Renting: A “Let’s Try This First” Mindset
One of the most practical decisions a newly diagnosed person faces isn’t CPAP versus BiPAP at all — it’s whether to buy a machine outright or try one on a trial basis first. This is exactly where opting for a CPAP machine on rent or a BiPAP machine on rent can take the pressure off an already overwhelming week.
Renting lets you live with a real machine, in your own bed, before committing to a purchase. It gives you room to test whether your prescribed pressure feels right, whether your mask choice needs adjusting, and whether CPAP alone is managing your symptoms or whether a conversation about BiPAP is worth having with your doctor. Our CPAP machine rental and BiPAP machine rental options are built for exactly this “let’s try this first” phase, so you’re not locked into a decision before you know what actually works for you.
If you’d rather own your equipment from day one but want to be mindful about it, it’s also worth comparing certified pre-owned CPAP machines and certified pre-owned BiPAP machines, which are inspected and serviced before resale. Whichever route you take, comparing Bipap Machine price and Cpap Machine price across new, pre-owned, and rental options is a reasonable first step, and our team is happy to talk you through what fits your prescription.
What to Expect in Your First Week of Therapy
The first week is almost always the hardest, and knowing that in advance makes it easier to push through. Here’s a realistic picture of what beginners commonly experience:
- Nights 1 to 3: Mask awareness is high. You may wake to reposition it, notice minor air leaks, or feel unusually aware of the hose, along with some nasal congestion or dryness as your airway adjusts.
- Nights 4 to 7: The mask typically starts feeling less foreign. You may still take it off in your sleep occasionally without remembering — common early on, and it tends to improve with time.
- Ongoing: Daytime energy and sleep quality improvements are often gradual rather than immediate. Give it real time before judging whether the therapy is “working.”
Small habits help: keep your mask and hose clean, use your machine’s humidification settings if it has them, and reach out to your provider early if something feels off. Our guide on how to properly clean your CPAP or BiPAP machine is worth bookmarking from day one. If you have a partner sharing the bed, our post on being supportive of a partner with sleep apnea is worth sharing too — adjusting to therapy is often a two-person experience.
Frequently Asked Questions
Is BiPAP better than CPAP?
Neither is universally “better” — they’re suited to different situations. CPAP delivers one constant pressure and is typically the first therapy prescribed for straightforward obstructive sleep apnea. BiPAP delivers two pressure levels and is generally introduced when someone needs higher pressure, finds exhaling against CPAP difficult, or has a more complex breathing pattern. Your sleep doctor’s recommendation is based on your specific sleep study results.
Can I choose to start with a BiPAP machine instead of CPAP?
This should be a decision made with your sleep physician, since it depends on your AHI score, pressure requirements, and any other breathing or health conditions. Most beginners with uncomplicated obstructive sleep apnea start with CPAP, but your doctor can advise if BiPAP is more appropriate for your case from the start.
How long does it take to get used to a CPAP or BiPAP machine?
It varies by person, but many beginners notice things feeling more natural within the first one to two weeks of consistent use. Mask fit, pressure comfort, and simply building the habit of nightly use all play a role in how quickly the adjustment happens.
What is aerophagia and is it dangerous?
Aerophagia is swallowing air during positive airway pressure therapy, which can cause bloating, burping, or gassiness. It’s uncomfortable but not dangerous, and it’s often improved by adjusting mask fit, addressing mouth leaks, or reviewing pressure settings with your provider.
Should I rent or buy my first sleep apnea machine?
Many newly diagnosed patients prefer to rent first. Opting for a CPAP machine on rent or a BiPAP machine on rent lets you test the therapy, mask style, and prescribed pressure in real conditions before deciding whether to purchase equipment outright.
What AHI score means I need a sleep apnea machine?
An AHI of 5 or higher indicates some degree of obstructive sleep apnea, and treatment is typically discussed starting in the mild range (5 to 15) and more strongly recommended for moderate (15 to 30) and severe (above 30) cases. Your doctor will weigh your AHI alongside your symptoms and overall health before recommending therapy.
Why does my mask leave marks or feel uncomfortable?
Mask discomfort is usually a fit issue rather than something you have to live with. An overly tight mask causes pressure marks, while a loose one causes leaks. Trying a different mask style — nasal pillow, nasal, or full-face — often resolves the problem within the first week or two.
Can I switch from CPAP to BiPAP later if I need to?
Yes. It’s common for someone to start on CPAP and move to BiPAP later if their pressure needs change or if CPAP isn’t fully controlling their symptoms. This switch is typically guided by a follow-up conversation with your sleep physician, sometimes alongside a repeat sleep study.
Figuring out CPAP versus BiPAP on your own can feel like a lot, but you don’t have to sort it out in isolation. If you’d like help matching your prescription and comfort needs to the right sleep apnea machine, mask, and rental or purchase option, get expert advice from our team or reach out through our contact us page — we’re happy to walk you through it.