A sleep study is a diagnostic test that involves recording multiple systems in your body while you sleep. Key body systems monitored include your brain, heart, breathing and more. This test isn’t painful and usually only takes one night to complete. This test is also very common and can help diagnose many sleep-related conditions.
A sleep study, formally known as a polysomnogram (pronounced “poly-som-no-gram”), is a diagnostic test that tracks and records how multiple body systems work while you’re asleep. This test involves sensors that track the activity of multiple body systems, including your heart, brain and respiratory system, giving healthcare providers a comprehensive view of the quality of your sleep.
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A sleep study is a diagnostic test, meaning that healthcare providers use it to diagnose or rule out health issues. Healthcare providers usually recommend this test when you have symptoms of conditions that affect sleep, to determine how to treat those conditions or to see if completed treatments worked. These are generally conditions that affect or disrupt your brain, nervous system, breathing and heart function.
Conditions that a sleep study can diagnose include:
Most sleep studies take place during your normal sleeping hours. Because most people sleep during nighttime hours, facilities that perform sleep studies (known as sleep labs) schedule most people for overnight sleep studies. However, people who work overnight hours and shifts — meaning they sleep during the day — can often schedule a daytime sleep study if necessary.
Sleep studies are very common. In 2014, people on Medicare accounted for more than 800,000 sleep studies. That doesn’t count the studies for people who aren’t on Medicare.
A sleep study involves several healthcare professionals. The people performing the sleep study are often medical technicians, technologists, assistants and nurses (including registered nurses and licensed practice nurses).
After you complete a sleep study, a physician (such as a pulmonologist or sleep medicine specialist) will review the test records for signs of any problems. They may also work cooperatively with other providers, such as a neurologist, primary care specialist or another provider you see, to get more info about your medical history or circumstances. They may also follow up with a provider you see to share the results so both providers can provide seamless, coordinated care.
An at-home sleep apnea test and a sleep study are similar but aren’t the same thing. An at-home sleep study typically doesn’t involve all of the sensors used in a sleep study. Some of the sensors that might not be used are those that detect brain wave activity, eye movement or your heart’s electrical activity.
An at-home sleep study usually involves sensors that detect breathing through your nose or mouth and movement of the breathing-related muscles in your chest and belly. These are usually reserved for cases where a provider strongly suspects sleep apnea or for follow-up testing to see if you still have sleep apnea after corrective surgery, weight loss, etc.
A sleep study involves these different sensors because the quality of your sleep can depend on many factors. Using multiple types of sensors, each tracking a specific body system or process, lets healthcare providers take an in-depth look at your sleep. That can make a big difference in diagnosing certain sleep-related conditions.
A sleep study involves the following sensors and monitoring methods:
A healthcare provider, usually a pulmonologist (a physician specializing in lung and breathing conditions) or a sleep medicine specialist, will recommend a sleep study based on your symptoms and health history. Once they do, they can often provide you with options for sleep labs in your area, and they may even be able to help you directly schedule with a sleep lab.
The scheduled time for your sleep study depends on your regular sleep habits, preferences, schedule and circumstances. Providers are most likely to recommend that you schedule your study at a time when you’re normally sleeping. It’s also common that sleep labs can schedule studies for people who sleep overnight or people who work at night and sleep during the day.
Preparing for a sleep study involves packing for an overnight stay and bathing/grooming for a medical procedure. While there might be some variations depending on sleep lab procedures and capabilities, the following are generally helpful to keep in mind while preparing:
On the day of your sleep study, you should mostly go about your usual routine. But there are also a few things you should keep in mind (unless your provider tells you otherwise):
After you arrive at the location where the sleep study is taking place, the healthcare providers who’ll oversee the study will take you to the room where you’ll stay the night. Once there, you’ll change into your sleepwear, and then the staff will go through the process of attaching the sensors to the various places on your body. Most of the sensors either have adhesive on them or need tape to attach them (if you have sensitive skin or adhesive allergies, be sure to tell the staff before they begin attaching the sensors).
After staff attach the sensors, they’ll have you do a few tasks to help them check that the sensors are working and calibrated correctly. The tasks are simple and include moving your eyes, opening/closing your mouth and moving your legs.
The sensor wires should be long enough to allow you to move comfortably in bed. However, if you need to get out of bed, a staff member may need to assist you in unplugging the wires. Don’t unplug them unless a staff member tells you how to do so correctly, or it might affect the sleep study results.
After staff members calibrate the sensors, you can relax and watch TV or read before going to sleep. Most people don’t sleep as well during a sleep study because it’s an unfamiliar environment or because of the sensors they’re wearing. However, this usually won’t impact your study’s results.
While you sleep, providers and personnel monitoring your sleep study may check on you under certain circumstances. These include:
In the morning, you’ll wake up and sleep lab personnel will help disconnect and remove all the sensors. After that, you can change into your clothes for the day and leave the sleep lab.
Very few side effects or complications can happen with a sleep study. These are most likely to be irritation from — or a reaction to — adhesives/tapes used to attach sensors. Another common effect is that people don’t sleep as well or for as long because they’re in an unfamiliar place.
There may be other possible complications, but these are uncommon and vary from person to person. A healthcare provider is the best person to tell you more about what’s likely in your case.
After the sleep study, a healthcare provider will review and interpret the data. That professional interpretation is key because a sleep study involves gathering multiple types of data about how you sleep. Seeing the big picture of a person’s sleep data takes years of education, training and experience. Once the provider interprets the data, they can determine if you have a medical issue and diagnose it.
After a provider interprets the data and arrives at the diagnosis, they’ll contact you to let you know what they found (if anything) and recommend next. In most cases, they’ll talk to you further about your results at a follow-up visit. They’ll also discuss treatment options and other next steps.
A healthcare provider should reach out to you within a few days after your sleep study to give you the results. This can vary depending on the facility, so it’s best to ask your provider when to expect the results after your study.
For most people, a single night in a sleep lab (or the equivalent of a night, for those who get a daytime sleep study) is all it takes. Experts and healthcare providers generally consider a sleep study valid if you sleep a total of two hours or more (but the more you sleep like normal, the more useful the data gathered).
For some people, more than one night in a sleep lab is necessary. That can be for multiple reasons, ranging from the condition suspected to whether or not the readings from the first night were sufficient for interpretation. A healthcare provider can tell you more about what they recommend for you and why.
Sleep studies do involve low-light cameras that can record video and audio. However, the sleep lab staff won’t watch you the whole time while you sleep. The cameras are mostly there so sleep lab staff can look at what’s happening if they get unusual or concerning readings. The cameras are also there to record what’s happening so providers can compare the recording to the readings from the sensors. That means unless a staff member has a specific reason to look at you through the camera, they probably aren’t watching you.
Yes, you can wake up at night to use the bathroom during a sleep study. But sleep lab staff will tell you whether or not you can do so without a staff member helping you. This varies depending on the sleep lab’s equipment, policies and room layout. You can ask about this if a sleep lab staff member doesn’t tell you before your sleep study begins.
Under almost all circumstances, a sleep study is something you do alone. There are cases, such as for children or people with special circumstances and needs, where a caregiver or loved one can also stay at the sleep lab. However, they’ll usually need to use another room to keep from affecting the readings and results of the sleep study.
In rare instances, a caregiver or loved one may be able to stay in the same room, but they can’t sleep in the same bed as the person undergoing the sleep study. This varies depending on the lab, type of test and more, so it’s best to talk to your healthcare provider or sleep lab staff.
No, a sleep study is painless. None of the sensors or other equipment will cause you any pain during the study. Taking off some of the sensors, which use tape or adhesives to stick to your skin, might cause mild discomfort, but staff can help minimize or prevent that when the study is over.
A note from Cleveland Clinic
A sleep study is a common diagnostic test that can help diagnose many conditions and sleep-related issues. Hundreds of thousands of sleep studies happen annually, and they’re a key part of diagnosing and treating conditions like sleep apnea, narcolepsy, restless leg syndrome and more.
While many people feel anxious or worried about this test, healthcare staff and providers who specialize in or participate in sleep study testing can help you relax and rest easy. That way, you can sleep, the test can gather info about how you sleep, and providers can determine if there’s a cause for concern and what they can do to help.
Last reviewed by a Cleveland Clinic medical professional on 02/10/2023.
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