The Number That Determines Your Diagnosis
After a sleep study, you'll receive a number that changes everything: your AHI score. Whether it's 7 or 70, this single figure determines your sleep apnea diagnosis, its severity, and which treatment options are right for you. Here's exactly what it means.
What Does AHI Stand For?
AHI stands for Apnea-Hypopnea Index. It measures the average number of breathing disruptions per hour of sleep. An "apnea" is a complete pause in breathing lasting at least 10 seconds. A "hypopnea" is a partial reduction in airflow — typically at least a 30% drop — accompanied by a fall in blood oxygen or a brief arousal from sleep. Your AHI is calculated by dividing the total number of events recorded by the total hours slept.
AHI Score Ranges and What They Mean
- AHI under 5 — Normal. Some breathing irregularities during sleep are expected and not clinically significant.
- AHI 5–14 — Mild obstructive sleep apnea. Treatment is recommended, especially if symptoms are present.
- AHI 15–29 — Moderate obstructive sleep apnea. Treatment is strongly recommended.
- AHI 30 or above — Severe obstructive sleep apnea. Prompt treatment is recommended.
What Treatment Is Right for My AHI?
For mild to moderate sleep apnea (AHI 5–29), oral appliance therapy is a first-line treatment endorsed by the American Academy of Sleep Medicine. A custom mandibular advancement device repositions the jaw to keep the airway open — often reducing AHI to below 5 in mild to moderate cases.
For severe sleep apnea (AHI 30+), CPAP is traditionally the first recommendation due to its higher efficacy at very elevated AHI levels. However, oral appliance therapy is an appropriate alternative for patients who cannot tolerate CPAP, and combination therapy is an option for patients who need additional airway support. The most important factor is consistent nightly use.
Other Metrics in Your Sleep Study Report
Your report will typically include more than just AHI. Other important measurements include oxygen desaturation index (ODI), minimum SpO2 (the lowest oxygen level recorded), sleep efficiency, and whether your AHI is higher during REM sleep versus NREM sleep. Your physician will consider all of these alongside your AHI when recommending treatment.