Normal sleep study numbers: AHI, ODI, SpO2 and the rest of the report

Normal AHI

An AHI below 5 events per hour is considered normal in adults. From 5 up, obstructive sleep apnea is present, and the severity bands and what to do about each are set out in what is AHI, and what score is dangerous.

One thing worth knowing before you compare your number with anyone else's: AHI is an average across the night. A night that averages 12 can hide a stretch of back-sleeping where the rate was three times that, which is why the position breakdown matters as much as the headline figure.

Normal oxygen numbers

Healthy overnight SpO₂ is roughly 94–98%. The report shows your average and lowest oxygen; a low nadir (for example dips below 90%) suggests apnea is affecting your oxygen. A low ODI (few desaturation events per hour) is reassuring.

Reading the numbers together

No single number tells the whole story. A normal AHI with strong symptoms may still prompt further testing, while a raised AHI with big oxygen dips and back-sleeping clustering paints a clearer picture. That is why a physician interprets the full report.

The numbers people skip

Recording time. A report built on four hours of recorded sleep is weaker evidence than one built on seven, and a short night can understate the AHI. Check it before you accept a reassuring result.

Snoring percentage and body position. Most reports break events down by position. Apnea that appears only when you sleep on your back is a different conversation with your doctor than apnea that happens in every position — sometimes a positional measure helps before anything else is considered.

Pulse. A heart rate that climbs with every event is a sign the body is working hard through the night, and it is part of why untreated apnea is linked to blood pressure. Sleep apnea and diabetes, blood pressure and heart disease covers that link.