Your Sleep Study Results, Explained: AHI, Oxygen and Severity

Opening a sleep study report can feel like reading a lab result in another language, and it's easy to fixate on one number without knowing what it means for you. The most important figure is your AHI, the average number of times each hour your breathing stopped or became very shallow, and it's what decides whether sleep apnea is mild, moderate or severe. In Glen Allen, we walk every patient through their report line by line, so the numbers turn into a plan you understand.

Understanding the AHI number

AHI stands for apnea-hypopnea index. An apnea is a pause in breathing, and a hypopnea is a stretch where breathing gets so shallow that your oxygen dips or your brain briefly wakes you. The report adds those events up and divides by the hours you slept, so an AHI of 12 means your breathing was interrupted about 12 times an hour, all night long.

Dr. Ashlee Goodman-Tabari often puts it in plain terms for patients: stopping breathing at least five times an hour is where sleep apnea starts, and that's only the mild range. "I've seen patients that stopped breathing a hundred times in an hour," she says. Most people are stunned by their number, because they had no idea any of it was happening.

Where your number falls: mild, moderate or severe

The American Academy of Sleep Medicine uses these adult ranges: an AHI of 5 to 15 is mild, 15 to 30 is moderate, and more than 30 is severe. Under 5 is generally considered within the normal range for adults. The severity rating matters because it shapes which treatments make sense.

For mild to moderate sleep apnea, a custom oral appliance is an effective option for people who prefer it to CPAP or haven't been able to stick with one, according to the AASM. For severe sleep apnea, CPAP is usually the first recommendation, and sometimes the two are used together. We explain the trade-offs in detail on our CPAP vs. oral appliance page.

Reading your oxygen levels

Your report will also show how low your blood oxygen dropped and how much of the night it spent below a healthy level. Each pause can pull oxygen down, and the AASM notes that in severe cases levels can fall 40 percent or more. Two people with the same AHI can have very different oxygen patterns, which is one reason we look at the whole report, not a single number.

Oxygen is also how we judge whether treatment is working. After your appliance is fitted and adjusted, we retest to confirm your breathing and oxygen have actually improved.

A normal AHI with ongoing tiredness

Sometimes the AHI comes back low and you still wake up exhausted. That can happen with upper airway resistance syndrome, where the airway narrows enough to disturb your sleep without fully stopping your breathing. Dr. Goodman-Tabari knows this one personally: it's what she has. "My oxygen levels still drop," she says. "I'm always tired."

If your study was called normal but your days say otherwise, it's worth another look. Our page on upper airway resistance syndrome explains why it's so often missed.

Talking through your report with us

Your home sleep test is a small wearable device you use in your own bed, and the results come back to us quickly. Because Dr. Goodman-Tabari is a dentist, a sleep physician reads the study and makes the diagnosis, and we coordinate that step so you don't have to chase it. Then we sit down with you, go through your AHI and oxygen numbers, and talk about what they mean for your health and your sleep.

From there, the plan depends on your results and your preferences. If an oral appliance fits, we scan, design and fit it, then follow up and retest. If a CPAP is the better match, we'll tell you so and work with your physician. You can see the steps on our what to expect page.

Common questions about sleep study results in Glen Allen

What is a normal AHI?

For adults, an AHI under 5 is generally considered within the normal range. An AHI of 5 to 15 is mild sleep apnea, 15 to 30 is moderate, and above 30 is severe. At A-Z Sleep & Airway Center in Glen Allen, we explain your number and oxygen readings together so you understand the full picture.

Is an AHI of 10 bad?

An AHI of 10 falls in the mild range, meaning your breathing was interrupted about 10 times an hour. Mild sleep apnea can still leave you tired and strain your health over time. In Glen Allen, we'll look at your oxygen levels and symptoms too, then talk through treatment options such as a custom oral appliance.

Does my oxygen level matter as much as my AHI?

Yes. Your AHI counts the breathing events, while your oxygen readings show how hard those events hit your body. Two people with the same AHI can have very different oxygen drops. At A-Z Sleep & Airway Center in Glen Allen, we review both and use a follow-up test to confirm treatment is working.

Who diagnoses sleep apnea after a home sleep test?

A sleep physician reads your home sleep test and makes the diagnosis. Dr. Goodman-Tabari is a dentist, so she treats sleep apnea with a physician's diagnosis in place. At our Glen Allen office, we coordinate that step for you, so you get answers without bouncing between offices.

What if my sleep study was normal but I'm still tired?

A normal AHI doesn't always mean normal sleep. Upper airway resistance syndrome can disturb your rest without fully stopping your breathing, so it's easy to miss. If you're still exhausted, Dr. Goodman-Tabari can review your history and results in Glen Allen and talk through whether further evaluation makes sense for you.

Making sense of your own numbers

Whether you already have a report in hand or you're wondering whether you need a test at all, we're happy to help you make sense of it. Call us at (804) 767-2507 or send us a message to schedule a consultation at our Glen Allen office. New to us? Start with our new patient page.