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Respiratory Sleep Study

Sleep studies encompass many general tests and sleep problems. When focusing solely on respiratory issues, the tests that are usually used include: the respiratory polygraphy sleep test, recording oxygen and carbon dioxide levels overnight and polysomnography (PSG)

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Everything you need to know

Sleep studies encompass many general tests and sleep problems. When focusing solely on respiratory issues, the tests that are usually used include:

  • Respiratory polygraphy sleep test
  • Recording oxygen and carbon dioxide levels overnight
  • Polysomnography (PSG)

Sleep studies are often conducted in the evening as that’s when most patients go to sleep; this will require some patients to stay overnight. However, if you’re a night worker or work on shifts, then we’ll make allowances and run the test in the daytime.

Depending on the monitoring equipment required for the test, many patients can do a test themselves at home; for example, sleep apnoea tests can be done in your own home.

To be certain that you require a test from the sleep centre, you’ll first need to contact the department and book an initial appointment. During this appointment, the doctor will run a few tests and assess whether you have symptoms associated with sleep-disordered breathing (SDB):

  • Waking from a full night of sleep still feeling tired
  • Daytime sleepiness
  • Headaches in the morning
  • Gasping, snorting, loud snoring, or choking during sleep
  • A disturbed sleep
  • Low oxygen levels
  • High carbon dioxide levels
  • Breathing that stops and starts while you sleep

To diagnose sleep disorders successfully, patients may need multiple sleep tests if they exhibit many symptoms. If you’re not sure if you have these symptoms, but you think you may need a sleep test, record yourself at night so that you can listen back and assess whether you need to make an appointment with us.

In general, a sleep test not only offers you a diagnosis, but it also will help the doctor create an appropriate and personalised treatment plan for you.


As mentioned previously, to gain access to a sleep study, you’ll first need to arrange an appointment with a physician at St John and St Elizabeth Hospital. The doctor will then ask a few questions and run some tests to determine whether a sleep study is right for you or not.

For further information, the doctor will also discuss your symptoms, ask you to complete a sleep questionnaire, discuss how long you’ve been impacted, your medical history, and whether you take any medication (for example, sleeping tablets, anti-depressants, or prescribed painkillers).

If you’re given the go-ahead to start a sleep study, the doctor will let you know whether it’ll be at the sleep unit or at home. Either way, there are protocols all patients must follow 24 hours before their test to not interfere with the results. For example:

  • avoid alcohol and caffeine
  • avoid napping prior to the test

You should be able to continue taking any regular medications – unless the doctor specifies otherwise.


A sleep study includes a range of tests. When a sleep specialist needs to monitor your respiratory system, you can expect them to recommend one of those three tests:

Respiratory polygraphy sleep test

A respiratory polygraphy is a test that can diagnose different types of breathing difficulties and assess the severity of them.

This type of test is usually conducted at home. The equipment can be picked up from the hospital and will include a chest and abdomen band to measure movement, a small flow sensor in the nostrils, and an oxygen monitor on the finger; you’ll need to wear these during the test.

The equipment is used to diagnose sleep-disordered breathing (SDB) which can diagnose conditions such as obstructive sleep apnoea (OSA).

While you wear the equipment, it will record your:

  • breathing
  • oxygen levels
  • heart rate
  • snoring
  • sleep position and movement.

Overnight oximetry

When focusing on your respiratory system, sometimes a sleep consultant will run a recording of your oxygen levels overnight.

Most often, this test is used to diagnose a sleep condition or ensure the current treatment plan that you’re on is effective.

This test may require an overnight stay, however, sometimes you’re able to pick it up and take it away with you. Before you fall asleep, you’ll put a small clip called a pulse oximeter on your finger (sometimes your earlobe) which will record your oxygen levels and heart rate overnight.

Patients with no underlying cardio-respiratory disease will have an oxygen level of between 95% – 98% at rest, however, if your oxygen level dips by 4% of that healthy range, then it could indicate that you’ve been holding your breath for at least 10 seconds. This disrupted sleep is concerning as it can be indicative of a larger problem or lead to other illnesses developing.

Polysomnography (PSG)  

A PSG is a piece of equipment that you can collect from the sleep centre and take away to use at home (but you will need to return it to the clinic the next day), however, you might be required you to wear it for an overnight stay.

A neurological sleep study will be recommended if you are showing signs of having a neurological sleep disorder. During the test you will wear breathing bands around the chest and abdomen and small disposable discs on your head attached using sticky water-soluble paste. Additional electrodes will be applied on the shoulder area to record heart rate and on the calf muscles to record muscle activity.

The sensors will then monitor your sleep and send the data to the team. A PSG is designed to assess:

  • brain activity
  • eye movements
  • heart rhythm
  • breathing signals
  • oxygen levels

The data gained from a PSG can help the team rule out sleep disorders such as obstructive sleep apnoea, narcolepsy, sleep-related seizure disorders, chronic insomnia, and more.

It’s important that you do reach out to the sleep centre for a diagnosis because if you are living with an untreated disorder, then it can raise your risk of:

  • heart disease
  • high blood pressure
  • stroke
  • depression


As each test requires you to be asleep, we typically require a full night’s worth of data for the most accurate reading.

If you had the test done at home, you’ll need to return the equipment the next morning. If you remained overnight in a sleep unit, then when you wake up, the sensors will be removed and you’ll be allowed to leave.

Regardless of the test that was performed on you, you’ll need to allow some time for the team to assess the data and review the information; this typically will take around a week.

Once your results are back in, you’ll be able to schedule a follow-up appointment. In this appointment, the doctor will go through the results with you. Based on these results and your symptoms, you’ll be given your diagnosis.

After the diagnosis, the doctor will work through a personalised treatment plan with you, prescribe you medication (if appropriate), and arrange regular check-ins to see how you’re getting on in a few months’ time.

How to pay for your treatment

If you’re… paying for yourself

Did you know you don’t need private medical insurance to come to St John & St Elizabeth Hospital? As a self-pay patient, you can access safe, outstanding quality health care at times to suit you.

For scans and tests, as well as to see most consultants, you’ll still need to be referred by a medical professional like your GP, but as a self-pay patient, the process is more straightforward. You won’t need authorisation from an insurance provider, and you’ll have greater choice of consultant and appointment times.

If you’re… insured

St John & St Elizabeth Hospital is approved by all major medical insurance companies. If you have a personal private health insurance policy, or your company provide it for you, you can use it to pay for your care from your initial consultation through to treatment, surgery and aftercare such as physiotherapy. Not all private health insurance plans cover the same things. It’s very important to check exactly what you are covered for with your insurance provider.