What happens during a sleep study, and do I need one?
If you or your partner have raised concerns about your breathing during sleep, or if a doctor has suggested that your snoring or daytime tiredness may have an underlying cause, a sleep study is likely to be one of the first investigations recommended. Yet for many patients, the idea of a sleep study still prompts uncertainty. What does it actually involve? Is it uncomfortable? Do I have to go to a hospital? And what will it tell us?
A sleep study is not an ordeal. It is a straightforward overnight recording that can, in a single night, answer questions that have gone unresolved for years.
A sleep study is often the point at which years of unexplained symptoms finally begin to make clinical sense.
The underdiagnosis problem
Over 80% of adults with moderate-to-severe obstructive sleep apnoea are estimated to remain undiagnosed, with some research placing the figure as high as 85–90%.
Sleep apnoea is estimated to affect around 4.8% of the UK population, roughly 1.5 million people with moderate or severe disease, yet multiple peer-reviewed studies consistently indicate that over 80% of those affected are unaware of their diagnosis. In some studies and selected populations, the figure approaches 85–90%.
Taken together, these figures suggest that the United Kingdom is home to well over a million people with clinically significant, untreated sleep apnoea, most of whom do not know it.
The sleep study is the investigation that finally gives a name to symptoms many patients have been dismissing, or having dismissed, for years.
Home sleep studies vs in-laboratory testing
Sleep studies can be performed either in a sleep laboratory, where you spend the night under observation in a clinical setting, or at home using a portable monitoring device. In the vast majority of cases, a home sleep study provides sufficient diagnostic information and is considerably more convenient and comfortable for the patient.
At Hillser Clinic, we use home-based sleep studies as our standard diagnostic tool for suspected obstructive sleep apnoea. The portable monitoring device is small and unobtrusive, and most patients find it has little impact on their sleep.
In-laboratory polysomnography, a more comprehensive test that monitors additional parameters including brain activity, eye movements and muscle tone, may be recommended where more complex sleep disorders are suspected, or where home testing has produced inconclusive results.
What does the device measure?
A home sleep study device typically records:
Respiratory effort: whether you are making breathing movements during sleep.
Airflow: whether air is actually passing through the nose and mouth, and whether this is interrupted.
Oxygen saturation: the level of oxygen in your blood, which drops when breathing is obstructed.
Heart rate: which provides additional information about the cardiovascular impact of any breathing disturbances.
Body position: since sleep apnoea is often worse when lying on your back.
Snoring sounds: recorded by a small sensor to characterise the pattern and severity.
How is it set up?
The device is provided during a clinic appointment or sent to you directly, with clear written and video instructions for self-application. Sensors are typically attached to the finger, chest and nose using simple adhesive or elastic fastenings. The setup takes around five to ten minutes and requires no clinical expertise.
You wear the device during a normal night's sleep in your own bed, then return it the following morning. The recorded data is downloaded and analysed by our clinical team, and the results are discussed with you at a follow-up appointment, usually within a few days.
Preparing for your sleep study
The night of your sleep study should, as far as possible, be a normal one. Avoid alcohol in the evening beforehand, as this can artificially suppress muscle tone in the throat and alter your breathing patterns, potentially affecting the accuracy of the recording. Continue any regular medications unless your clinical team has specifically advised otherwise.
There is no need to change your sleep routine, sleeping environment or bedtime. The device should be applied following the written and video instructions provided, and setup typically takes no more than five to ten minutes. If the recording is disrupted during the night, for example by the device shifting position, the clinical team will review the data quality and advise whether a repeat recording is required, though this is uncommon.
Who should have a sleep study?
A sleep study is recommended if you experience any combination of the following:
Loud or irregular snoring, particularly if witnessed pauses in breathing have been noted.
Excessive daytime sleepiness that is not explained by insufficient time in bed.
Waking unrefreshed despite adequate sleep duration.
Morning headaches, dry mouth, or frequent night-time waking.
Poor concentration, irritability or low mood that may be linked to poor sleep quality.
A sleep study is painless, carries no risk, and provides the clinical team with objective information that cannot be gathered from a consultation alone.
What happens after the results?
Once the data has been analysed, your results will be expressed as an Apnoea-Hypopnoea Index (AHI), a measure of the number of breathing events per hour of sleep. This figure, combined with your oxygen saturation data and clinical history, allows your clinician to determine the appropriate next steps. These may range from lifestyle advice for mild cases through to CPAP therapy or further investigation with drug-induced sleep endoscopy (DISE) for more significant findings. Our snoring and sleep wellness service covers the full treatment pathway from diagnosis through to care.
Frequently asked questions about sleep studies
Will I be able to sleep with the device on?
Most patients sleep normally with the device in place. The sensors are small, lightweight and attached using simple adhesive or elastic fastenings that most people find comfortable within a few minutes of application. Occasionally patients report mild awareness of the device in the first hour of the night, but this typically resolves once they are settled.
Is a home sleep study as accurate as a laboratory test?
For the diagnosis of obstructive sleep apnoea, home sleep studies are well-validated and provide clinically reliable results in the majority of patients. In-laboratory polysomnography measures a broader range of parameters and is typically reserved for cases where a more complex sleep disorder is suspected, or where a home study has produced inconclusive findings. Your clinician will advise which type of study is most appropriate for your situation.
How long does it take to get my results?
Results are typically reviewed and available within a few days of the device being returned. You will then be offered a follow-up appointment to discuss what the data shows and what, if anything, the next steps should be. The Apnoea-Hypopnoea Index produced by the study gives a clear, objective measure of the frequency and severity of any breathing disturbances during sleep.
What if my results come back normal?
A normal result is useful clinical information. If your sleep study shows no significant breathing disturbances, it allows other causes of your symptoms to be explored and rules out obstructive sleep apnoea as a contributing factor. Your clinician will review the results in the context of your full clinical history and advise on appropriate next steps, which may include further investigation or reassurance.
Can I have a sleep study if I travel or work shifts?
Yes. Because the home sleep study uses a portable device worn in your own bed, it can be arranged around your schedule, including during periods of travel or shift work, provided the night of recording is a reasonably representative one. Your clinical team will advise on any specific considerations relevant to your circumstances, including whether to avoid study nights immediately following unusual sleep patterns such as overnight flights or very disrupted shifts.
Do I need a referral for a private sleep study?
No referral is required to arrange a private sleep study at Hillser Clinic. You can self-refer directly by contacting our team, and the assessment process, including a clinical consultation, the sleep study itself, and results review, can typically be completed within a short timeframe. This is one of the significant advantages of the private pathway for patients who have been waiting for NHS assessment.
Book a sleep study at Hillser Clinic
If you are concerned about your sleep quality, have been told you snore or stop breathing during the night, or are experiencing unexplained daytime fatigue, a home sleep study is a straightforward and informative first step. We offer specialist assessment of sleep-disordered breathing at Hillser Clinic, with rapid access to home sleep studies, results review and a full range of treatment options. To arrange a consultation or enquire about a sleep study, please contact our team.
