How to Read Your Sleep Apnea Diagnosis
How to Read Your Sleep Apnoea Diagnosis
Getting a new sleep apnoea diagnosis can feel like learning a new language.
From AHI scores to RDI and oxygen saturation, the terms and numbers might seem overwhelming at first.
The good news? Once you know what each measurement means, it all becomes much clearer—and you’ll better understand how to manage your therapy.
This guide breaks down the key sections of your sleep report and explains how they relate to your treatment plan.
Understanding a Sleep Apnoea Breathing Event
During the night, your airway may partially or fully close, causing your breathing to stop or become shallow for 10 seconds or more.
These interruptions are called:
- Apnoea events – full pauses in breathing
- Hypopnoea events – shallow breathing that lowers oxygen levels
To be formally diagnosed with sleep apnoea, you must experience five or more breathing events per hour on average.
Without treatment, some people experience 20 or more events every hour.
With effective CPAP therapy, these events can drop dramatically—often to less than one per hour.
The Apnoea–Hypopnoea Index (AHI)
The AHI is a key number on your sleep report. It measures how often breathing interruptions occur per hour, including both apnoea and hypopnoea events.
- Normal: Fewer than 5 events/hour
- Mild: 5–15 events/hour
- Moderate: 15–30 events/hour
- Severe: More than 30 events/hour
Higher AHI scores mean more severe sleep apnoea and a stronger need for ongoing therapy.
After your sleep study, you’ll receive a detailed report showing how sleep apnoea affects your body. Here’s what each key section means.
RDI – Respiratory Disturbance Index
RDI measures all breathing disturbances—including apnoea, hypopnoea, and subtler irregularities that can still fragment sleep.
It’s possible to have an AHI under 5 but an RDI high enough for a diagnosis, especially if you have frequent arousals or shallow breathing.
Oxygen Saturation
Healthy oxygen saturation while sleeping is 96–97%.
Repeated breathing interruptions can drop levels below 95%, causing oxygen desaturation, which strains your heart and brain.
Treatment aims to maintain normal oxygen throughout the night.
Sleep Pulse
Your report also lists heart rate during sleep.
Sleep apnoea often increases heart-rate variability as your body repeatedly wakes to restart breathing.
Snoring
The report includes snoring volume, total minutes snored, and what percentage of the night this occurred.
While not everyone who snores has sleep apnoea, it’s a common symptom linked to airway blockage.
Body Position
Many people experience more breathing events when lying on their back.
Tracking sleep position can help guide therapy or simple lifestyle changes, like side-sleeping.
Sleep Stages
Normal sleep cycles through light, deep, and REM (dreaming) stages.
Apnoea is most common in deep and REM sleep, when muscles relax most.
True Sleep Time
This shows how long you were actually asleep, not just in bed.
If you spend eight hours in bed but only sleep six because of breathing events, your report will capture this difference.
CPAP therapy aims to increase true sleep time so you wake up more refreshed.
Monitoring Events During CPAP Therapy
Modern CPAP machines continue to monitor your events per hour to confirm that treatment is working.
Most users see a drop to below 5 events per hour, and many reach 0–1 events per hour.
If your event rate seems high, don’t adjust your pressure settings on your own.
Instead, speak with a sleep professional or use an auto-adjusting CPAP device that adapts pressure breath by breath.
Key Takeaways
- AHI measures the number of apnoea and hypopnoea events per hour and determines severity.
- RDI captures all breathing disturbances, even subtle ones.
- Oxygen saturation, snoring, and sleep stages reveal how apnoea affects your overall sleep quality.
- True sleep time shows how much real rest you’re getting, not just time in bed.
With the right understanding and support, you can go from 20+ breathing events per hour to near-zero—and feel the benefits of deeper, more refreshing sleep.