A polysomnography test is a comprehensive, multi-channel sleep study that records your brain activity, breathing patterns, heart rate, oxygen levels, and body movements while you sleep. It is used to diagnose a range of sleep disorders, including obstructive sleep apnea, insomnia, and restless legs syndrome. The sections below walk through everything you need to know, from how the test works to where you can access sleep testing in Alberta.
How does a polysomnography test work?
A polysomnography test works by attaching a series of sensors to your body before you fall asleep. These sensors continuously record physiological data throughout the night, giving clinicians a detailed picture of what happens to your body during each stage of sleep. The recording captures multiple channels of information simultaneously, which is what makes it such a thorough diagnostic tool.
During the study, sensors are placed on your scalp to measure brain wave activity, around your eyes to detect eye movements, and on your chin to track muscle tone. Elastic belts around your chest and abdomen measure breathing effort, while a small clip on your finger monitors blood oxygen levels. Electrodes on your legs detect limb movements, and a microphone may be used to record snoring.
A sleep technologist reviews the collected data after the study is complete. The recording is divided into 30-second segments called epochs, each of which is scored according to established sleep staging criteria. This process produces a detailed report that your physician or sleep specialist uses to make a diagnosis.
What conditions can a polysomnography test diagnose?
A polysomnography test can diagnose a wide range of sleep disorders by capturing detailed physiological data across the full night. The most commonly identified conditions include obstructive sleep apnea, central sleep apnea, periodic limb movement disorder, restless legs syndrome, narcolepsy, and certain parasomnias such as sleepwalking or REM sleep behavior disorder.
Obstructive sleep apnea is among the most frequently diagnosed conditions through sleep testing. It occurs when the upper airway repeatedly collapses during sleep, causing pauses in breathing and drops in blood oxygen levels. Left untreated, it is associated with an increased risk of cardiovascular problems, daytime fatigue, and reduced quality of life.
The test is also valuable for identifying less obvious conditions. For example, periodic limb movement disorder, where the legs jerk repeatedly during sleep, can significantly fragment sleep without the person being fully aware of it. Narcolepsy, a neurological disorder affecting the brain’s ability to regulate sleep-wake cycles, can also be evaluated through specialized sleep testing protocols.
What’s the difference between a home sleep test and a polysomnography?
The key difference between a home sleep test and a polysomnography is the number of channels recorded and the setting in which the study takes place. A home sleep test, also known as a Level 3 sleep study, is a portable, streamlined version that you complete in your own bed. It focuses primarily on breathing patterns, oxygen levels, heart rate, and airflow, which makes it highly effective for diagnosing sleep-disordered breathing such as obstructive sleep apnea.
A Level 3 home sleep test is a well-established and clinically accurate diagnostic tool. For many patients, it provides all the information a sleep specialist needs to confirm a diagnosis and begin treatment. It is also significantly more accessible, with shorter wait times and the comfort of sleeping in a familiar environment.
The most important thing to understand is that getting tested matters. Whether a Level 3 home sleep study is appropriate for your situation is something your sleep specialist or referring physician can help you determine. The goal is always to reach an accurate diagnosis as efficiently as possible so that treatment can begin and your sleep quality can improve.
How should you prepare for a polysomnography test?
Preparing for a polysomnography test involves a few straightforward steps that help ensure the recording is as accurate as possible. You should avoid caffeine and alcohol on the day of the study, as both can interfere with sleep architecture and affect the quality of the data collected. Arriving with clean, dry hair makes it easier for technologists to attach the scalp sensors.
- Avoid caffeine from the afternoon onward on the day of your study
- Skip alcohol entirely on the day of the test
- Wash your hair and avoid applying any hair products, gels, or oils
- Bring comfortable sleepwear and any personal items that help you relax
- Continue taking any regular medications unless your doctor advises otherwise
- Avoid napping on the day of the study so you are tired enough to fall asleep
It is also a good idea to arrive a little early so you have time to settle in before the sensors are applied. The setup process typically takes 30 to 60 minutes, and most people find they can still fall asleep despite the equipment once they relax.
How are polysomnography results interpreted?
Polysomnography results are interpreted by a sleep physician who reviews the scored data from your overnight recording. The report includes a range of measurements that together paint a picture of your sleep health, with the most commonly referenced metric being the Apnea-Hypopnea Index, or AHI, which counts the number of breathing disruptions per hour of sleep.
An AHI of fewer than five events per hour is generally considered normal in adults. Mild sleep apnea falls between five and fourteen events per hour, moderate between fifteen and twenty-nine, and severe at thirty or more. These thresholds guide treatment decisions, including whether CPAP therapy is recommended and at what pressure settings.
Beyond the AHI, the report includes information about sleep stages, oxygen saturation levels, limb movement frequency, and the percentage of time spent in each stage of sleep. A sleep specialist reviews all of these data points together before making a diagnosis. Once a diagnosis is confirmed, a personalized treatment plan is developed, which for many patients includes CPAP therapy. Consistent CPAP use has a well-documented impact on reducing daytime fatigue, improving concentration, and supporting overall cardiovascular health.
Where can you get a polysomnography test in Alberta?
In Alberta, sleep testing is available through both public health facilities and private sleep clinics. Private clinics often offer faster access to diagnostic testing, including Level 3 home sleep studies, which are an accurate and effective way to diagnose sleep-disordered breathing without a lengthy wait.
How Dream Sleep Respiratory helps with sleep testing
At Dream Sleep Respiratory, we offer accessible sleep testing across Alberta, with clinic locations in Calgary, Edmonton, Red Deer, Olds, Canmore, Cochrane, and Lethbridge. We specialize in Level 3 home sleep studies, which allow you to complete your sleep test in the comfort of your own home while still receiving a clinically accurate diagnosis. Our team of experienced sleep specialists and respiratory therapists reviews your results and works with you to develop a personalized care plan tailored to your needs.
- Level 3 home sleep studies completed in your own environment
- Diagnosis reviewed by qualified sleep specialists and respiratory therapists
- Personalized treatment plans, including CPAP therapy where indicated
- Ongoing support, machine adjustments, and follow-up appointments
- Multiple locations across Alberta for convenient access to care
Starting treatment after a confirmed diagnosis can make a meaningful difference to your energy levels, sleep quality, and overall well-being. If you have been experiencing symptoms such as chronic snoring, morning headaches, or excessive daytime tiredness, getting tested is the most important first step. Contact us today to book your sleep study and take that first step toward better sleep.
Frequently Asked Questions
How long does it take to get polysomnography results, and what happens next?
After your sleep study, a sleep physician typically reviews and interprets the scored data within one to two weeks, though timelines can vary depending on the clinic and whether you completed an in-lab or home sleep test. Once your results are ready, your sleep specialist will walk you through the findings, explain your diagnosis, and discuss treatment options. If CPAP therapy is recommended, many clinics, including Dream Sleep Respiratory, can move quickly to set you up with the right equipment and pressure settings so you can begin treatment without unnecessary delays.
What if I can't fall asleep during the polysomnography test?
It is completely normal to feel anxious about sleeping in an unfamiliar environment with sensors attached, and sleep technologists are well aware of this. In most cases, even a few hours of recorded sleep is enough to collect the data needed for an accurate diagnosis. To improve your chances of falling asleep, avoid napping on the day of the study, skip caffeine after noon, and bring items that help you relax, such as your own pillow or comfortable sleepwear. If sleep remains very difficult, your physician may discuss whether a repeat study or an alternative testing format, such as a home sleep test, is more appropriate for you.
Can children undergo a polysomnography test, and is the process different for them?
Yes, polysomnography is used to diagnose sleep disorders in children as well as adults, and it is particularly valuable for identifying pediatric obstructive sleep apnea, which can affect growth, behaviour, and learning if left untreated. The process is largely the same, though pediatric sleep studies use age-specific scoring criteria and the AHI thresholds used to classify severity differ from those applied to adults. Children typically complete in-lab studies rather than home sleep tests, and a parent or guardian is usually permitted to stay with the child throughout the night to help them feel comfortable.
Is a referral required to book a sleep study in Alberta?
In Alberta, a physician referral is generally required to access publicly funded sleep testing through the health system, which can contribute to longer wait times. Private sleep clinics, however, may have different intake processes that allow for faster access to diagnostic testing. At Dream Sleep Respiratory, the team can help guide you through the referral process and works to minimize wait times so you can get tested and start treatment as quickly as possible. If you are unsure whether you need a referral, contacting the clinic directly is the easiest way to find out what steps apply to your situation.
What is CPAP therapy, and how soon after diagnosis would I need to start it?
CPAP, which stands for Continuous Positive Airway Pressure, is the most common and effective treatment for obstructive sleep apnea. It works by delivering a gentle, steady stream of pressurized air through a mask, which keeps the upper airway open during sleep and prevents the breathing disruptions identified in your polysomnography results. If CPAP therapy is recommended following your diagnosis, your sleep specialist will determine the appropriate pressure settings based on your study data, and you can typically begin treatment within days of receiving your results. Most patients notice improvements in daytime energy and sleep quality within the first few weeks of consistent use.
What are the most common signs that someone should ask their doctor about a sleep study?
The most frequently reported symptoms that prompt a referral for sleep testing include loud or chronic snoring, waking up gasping or choking, persistent morning headaches, excessive daytime sleepiness despite a full night in bed, and difficulty concentrating or remembering things. Bed partners often notice breathing pauses during sleep before the individual is aware of them, which is another strong indicator worth mentioning to your doctor. Because many sleep disorders develop gradually, people often adapt to feeling tired and do not recognize it as abnormal, making it worth discussing with a physician even if your symptoms feel mild or manageable.
Can a polysomnography test rule out a sleep disorder if results come back normal?
Yes, a normal polysomnography result is clinically meaningful and can help rule out conditions such as obstructive sleep apnea or periodic limb movement disorder. However, it is important to understand that a single overnight study captures one night of sleep, which may not fully represent your typical sleep patterns, particularly if you slept unusually well or poorly during the recording. If your symptoms persist despite normal results, your sleep specialist may recommend additional testing, such as a Multiple Sleep Latency Test to evaluate for narcolepsy, or explore other potential causes of your sleep difficulties, including lifestyle factors, anxiety, or underlying medical conditions.