How to read your sleep study report: AHI, ODI and SpO2 explained
Last updated: 2026-09-06
Quick answer
On a sleep study report, AHI is the number of breathing events (apneas and hypopneas) per hour: under 5 is normal, 5–15 mild, 15–30 moderate, over 30 severe sleep apnea. ODI counts oxygen-drop events per hour, and SpO₂ shows your blood oxygen — dips below 90% matter. A doctor interprets these together.
What is AHI on your report?
AHI (Apnea–Hypopnea Index) is the average number of times per hour your breathing stopped (apnea) or became shallow (hypopnea). It is the headline number: under 5 is normal, 5–14.9 is mild, 15–29.9 is moderate, and 30 or more is severe obstructive sleep apnea.
What is ODI?
ODI (Oxygen Desaturation Index) is how many times per hour your blood oxygen dropped by a set amount (often 3% or 4%). A high ODI alongside a high AHI confirms that the breathing events are pulling your oxygen down, which is what stresses the heart over time.
What does SpO2 mean?
SpO₂ is your blood oxygen saturation, as a percentage. Healthy overnight values sit at 94–98%. The report shows your average and lowest SpO₂; repeated dips below 90% are a sign that sleep apnea is affecting your oxygen levels.
Which numbers should you focus on?
Look at AHI for severity, ODI and lowest SpO₂ for the oxygen impact, and the position data (whether events cluster when you sleep on your back). These together guide whether therapy such as CPAP is advised — a decision your doctor makes with you.
Related: sleep study pricing · cost in Kerala · CPAP & BiPAP rental · home test in Kozhikode · book a test
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