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Symptoms and diagnosis - Obstructive sleep apnoea

Obstructive sleep apnoea is when your breathing stops and starts while you sleep. This happens because the walls of the throat relax and narrow. They block the flow of air into your lungs.

Obstructive sleep apnoea can regularly disrupt your sleep. This can have a big impact on your quality of life. If it is not treated, it can lead to other problems.

Symptoms of obstructive sleep apnoea

Many people with obstructive sleep apnoea do not know they have it. Often a partner, friend or family member first notices problems while you sleep.

Signs of obstructive sleep apnoea while you sleep include:

  • loud snoring
  • noisy breathing
  • long gaps between breaths
  • gasping or snorting

You may also:

  • have night sweats
  • wake up a lot during the night to pee
  • feel tired during the day

Diagnosing obstructive sleep apnoea

It can be hard to tell if you have obstructive sleep apnoea. It may help to ask someone to stay with you while you sleep so they can check for symptoms.

Non-urgent advice: Talk to your GP if:

  • you think you might have obstructive sleep apnoea

They can rule out other reasons for your symptoms. They may refer you to a specialist sleep clinic.

How your GP can help

Your GP will ask you about your symptoms. For example, how sleepy you feel during the day.

They will take your blood pressure. Sometimes they will take a blood sample. They can use the sample to rule out other conditions, such as an underactive thyroid (hypothyroidism).

How you can help with getting a diagnosis

There are some things you can do to help get a diagnosis.


  • ask a partner or friend to watch you while you sleep - they may be able to spot episodes of apnoea

  • keep a sleep diary - including how tired you feel and how often you fall asleep during the day

Sleep clinic

The sleep specialists will ask you about your symptoms and take a medical history. They may also do a physical examination.

Your sleep may be assessed in the clinic overnight or they may give you a monitoring device to take home.

Testing at a sleep clinic

The main test to assess sleep at a sleep clinic is a polysomnography (sleep study).

A polysomnography measures your:

They may also use sound or video recording equipment.

The doctor will use the test to diagnose obstructive sleep apnoea. They will find out how much it is interrupting your sleep and recommend treatment.

Testing at home

The specialist will show you how to use a device to monitor your sleep at home.

The device records your:

  • oxygen levels
  • breathing movements
  • heart rate
  • snoring during the night

The test can show if you have sleep apnoea and how severe it is. This is based on how often your breathing stops while you sleep (AHI score).

The clinic will base its treatment on your AHI score.

Treating obstructive sleep apnoea

What your AHI score means

The apnoea-hypopnoea index (AHI) measures how severe your sleep apnoea is.

How severe it is depends on the number of sleep apnoea episodes you have in an hour.

  • mild: 5 to 14
  • moderate: 15 to 30
  • severe: over 30

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 13 September 2023
Next review due: 13 September 2026

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.