Sleep study (polysomnography / home sleep apnoea test)

Category: Lung & Breathing Tests · All lung & breathing tests

What it is

A sleep study records what happens to breathing, oxygen levels, heart rate and (in laboratory studies) brain waves during sleep. Simpler home tests measure airflow, chest movement, pulse and oxygen; full polysomnography in a sleep laboratory adds brain, eye and muscle channels and video.

Why it is done

It diagnoses sleep apnoea (repeated pauses in breathing during sleep), investigates loud snoring, unexplained daytime sleepiness, and other sleep disorders such as periodic limb movements or unusual night behaviours.

How to prepare

Home kits are issued with instructions and worn for one or two nights. For laboratory studies, arrive in the evening with nightwear; tell the team about medicines, skin conditions and allergies to adhesives. Avoid caffeine and naps on the study day if advised; most medicines continue as usual.

What happens during the procedure

Sensors are attached with tapes and belts: bands around chest and abdomen, a soft probe on a finger for oxygen, a small cannula under the nose for airflow, and — for full studies — electrodes on the scalp, face and legs. You then sleep as normally as possible while recording runs.

Afterwards — recovery & results

The equipment is removed in the morning (or the home kit returned) and you go about your day. Data are scored by specialists; results typically take a few weeks and are discussed in clinic, including whether treatment such as CPAP is recommended.

Risks & considerations

There are no significant risks — mild skin irritation from adhesives is the main issue. An imperfect night's sleep is expected; studies are usually still interpretable, and a technically poor study can be repeated.

Watch: Sleep study (polysomnography / home sleep apnoea test) videos

Real procedure videos from the MedicalVideos.com library. Some clinical footage is graphic — that is the nature of a medical video library.

▶ WatchSleep apnea studyWatch on MedicalVideos.com

Frequently asked questions

What is CPAP and will I need it?

CPAP is a bedside machine delivering gentle air pressure through a mask to keep the airway open. It is the main treatment for moderate-to-severe obstructive sleep apnoea; your results and symptoms decide together.

I slept terribly — is the study wasted?

Usually not. Even a few hours of recorded sleep across positions and sleep stages answer the main questions.

Related procedures — Lung & Breathing Tests

Bronchoscopy Cardiopulmonary exercise test (CPET / CPEX)Chest drain insertion FeNO test (exhaled nitric oxide)Full lung function tests (PFTs with gas transfer)Methacholine challenge test (bronchial provocation)

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Please note: This page is educational information about a medical procedure or test. It does not replace the instructions of your own care team, who know your situation and whose preparation, fasting and medication advice you should follow if it differs from anything here. If you have symptoms that worry you, or an appointment you do not understand, contact your clinical team.