What Can I Expect From A Sleep Study?


Getting a sleep study any time soon? How do you feel about it? Some persons experience minor trepidation, others swing the opposite way towards eagerness. You may even be somewhere in-between!?Ultimately though, it’s important to have an understanding of what the process is all about. With that in mind, this writeup is geared at helping you answer the question of what to expect from a sleep study. Let’s dive in!

What’s a Sleep Study?

A sleep study, also known as polysomnography, is essentially a medical procedure which collects specific information about your sleep patterns. Said information may include things like the level of oxygen in your blood, your heart rate and blood pressure, brain waves and respiratory rate. This heap of data?is used subsequently to diagnose whether or not you may have a sleep disorder. It may sound simple but a TON of data can come out of a single study, so don’t for a second think that analysis is trivial. Your?sleep specialist needs to have as much information about you on hand in order to recommend the best possible treatment for you.

Why Would I Need a Sleep Study?

Teen with irregular sleepHave you ever heard about sleep architecture? There’s a lot that happens between the time you close your eyes at night and then wake up in the morning. For many of us who unfortunately wake up feeling tired and cranky on a regular basis, this downright mysterious process can be a true source of frustration. Getting a study done is surefire way of lifting the shroud around your specific pattern of sleep. Knowledge is power, and with a solid course of treatment , your quality of life can be improved dramatically.

As an example, my wife is an epilepsy patient. She experienced a concussion at the age of 14 and has been on anticonvulsants ever since. In her mid-20s, she started having terrible daytime fatigue, which we didn’t understand. Thinking that this was all related to her medication, we sought to have have her drugs decreased safely. 5 years later it was still the same, and getting worse. Interestingly enough, I came across a book by the name of Conquering Concussion, which gave us a whole new perspective on brain trauma and its impact on sleep. As it turns out, there was a pulmonologist right down the hall from her neurologist! He recommended a sleep study and, based on results, subsequently put her on CPAP. Long story short, she’s now back at school doing an Associates Degree in Fine Arts, something she would never have been able to do 1 year ago.

My take on this:?if you have received a recommendation for getting a sleep study done, waste no time. The keys to a better life may be right around the corner. It’s a great way of to get a “big picture” view of what’s happening during your sleep, and can help decrease some of the fear and frustration that comes with insufficient rest.

What Types of Sleep Studies Are There?

Sleep data collection

It isn’t immediately apparent that there are actually three (3) major types of studies available at sleep clinics. We will outline each below, with he first being the primary and the remaining two being adjunctive (in most instances).

  • Polysomnogram (PSG): This is usually a study done overnight at the sleep clinic. A registered polysomnography technician monitors all your vitals while you sleep inclusive of eye activity, heart rate, oxygen saturation, movements of your limbs and much more. This can help the specialist assess what sleep disorder(s) you may have, such as obstructive, central or complex (mixed) sleep apnea, periodic limb movement disorder (PLMD) or sleep-related seizures.
  • Multiple Sleep Latency Test (MSLT): This test oftentimes follows a polysomnogram and is performed during the day. ?It consists of several nap periods spaced a few hours apart. Data is collected during these naps so as to verify what happens with your sleep cycle (data on how long you actually take to fall asleep is also collected). It’s a great way of verifying if you may have excessive daytime sleepiness or narcolpesy, and thus can contribute to a solution. It can also help to confirm if previously prescribed treatment is actually working for you, thus permitting your specialist to either fine tune his/her recommendation or go for an alternate solution altogether.
  • Maintenance of Wakefulness Test (MWT): Like the MSLT, this is also a daytime study. It’s focus is somewhat different however. In an MSLT, the assumption is that the sleepier you are, the faster and more likely you will be to fall asleep given an opportunity to nap. An MWT instead aims to verify your level of wakefulness/alertness during daytime hours. The fundamental reason for this is to determine if your sleepiness could be a safety issue both for you personally and those around you. Remember the New Jersey Train Crash which raised serious awareness of the dangers of untreated sleep apnea? This is one of those sleep screening techniques which would have helped prevent it from happening in the first place! As a result, employers (particularly those involved in public transporation or other mission-critical public services involving the need to operate complex machinery) will usually require employees with a history of sleep-related issues to undergo this type of test.

How Do I Prepare For a Study?

First thing’s first, maintain your usual routine as much as possible. Doing anything else may throw off your results. There are a three (3) specific guidelines that ought to be observed however:

  1. Avoid caffeine, alcohol or any substance that may affect your sleep
  2. Avoid daytime napping
  3. Wash you hair so as to get rid of any grease, oils or gels (these may interfere with the electrodes on your scalp later)

Normally you will be asked to arrive at the sleep center at some time between 6pm and 9 pm. As part of the process, you will be asked to fill out some paperwork. You should ideally pack an overnight bag, with your (favourite) pajamas, a change of clothes for the following morning,?your toiletries/bathroom supplies and any medications that you require. It’s also a good idea to bring anything that normally helps you relax before sleeping (such as your Kindle, etc). Should you have any special concerns, please be sure to raise this with the clinic beforehand so that they can help to maximise your comfort. Also, make sure you have your dinner before arrival! Sleeping on an empty stomach is anything but comfortable.

What Happens During the Study?

sleep study wiringOnce you’re all ready for bed, the assigned sleep technologist will fit you up with an array of sensors. These will include sensors?for your scalp, temples, chest, arm and leg. These are all attached using tape or some other mild adhesive. In some cases a small mic may also be used to capture?snoring as well. It may be a lot of wires, but they’ll all be long enough for you to be able to move around comfortably. You may also be provided with a brief familiarisation session with PAP technology (positive airway pressure) since this may be used during the study to investigate its effects on your sleep.

After the fitting process and some reassurance, it’s lights out.?You’ll usually be in your own room, and it will be dark and separated from the sleep technologist’s monitoring station. Don’t be worried about falling asleep–most persons are actually surprised at how much they slept for the night after a PSG study. Additionally, do note that you do not need a full night of sleep for a study to be effective/accurate!

If you need to go to the bathroom simply indicate same to the technician. They may be directly within earshot or your room may be fitted with an audio system. In either case, you will be acknowledged and the sensors will be removed to facilitate your request.

What Data Is Collected?


The sleep technologist will be awake for the entire duration of your study, monitoring?the collection of data and making note of any special events. These will be represented on time-based, continuous graphs that will permit correlation of significant events by a sleep specialist.

technician monitoringThe following information will be collected:

  • Oxygen saturation (ie blood oxygen levels)
  • Body position and limb movement
  • Heart rate and blood pressure
  • Brain waves
  • Eye movement
  • Respiratory effort/stress
  • Snoring (and/or other airway-related noises you may make while asleep)

What’s Next When The Study Is Complete?

You’ll be aroused, normally at around 7am the following morning. More paperwork will follow, and then you’ll subsequently be released. Note that the technologist will not be able to share the results with you since they will first need to be analysed by the specialist. Once you’ve wrapped up, you can make your way to your other appointments that you may have planned. Some facilities may be outfitted with washroom conveniences which would allow you to shower etc so you can skip the commute home.

In around 1-2 business weeks you will be contacted for a consultation session. This session will basically involve the specialist going over your results, specifying what indicative markers you may have for sleep disorders (if any) and what treatment options may be available. You may be given a prescription to obtain said treatments or a referral if another specialist’s opinion (possibly from another discipline) may be necessary to corroborate the findings or investigate further issues.

Pay very close attention to what the sleep specialist tells you and ask questions if you are unclear about ANYTHING. Your results may explain a great many factors that influence your sleep and overall well-being. As a direct example, many persons do not realise that frequent bathroom visits during the night may be a sign of sleep apnea. When the body enters respiratory stress due to a closing airway (typical of sleep apnea patients), it triggers the release of adrenaline within the body (also known as the ‘fight-or-flight’ response). A direct impact of this is sudden arousal?which restores regular breathing…but accompanying same is renal stimulation, so the urge to flush the bladder provokes a trip to the lavatory. While bathroom trips could happen a few times per night, actual sleep/wake events could occur hundreds of times, leaving the patient feel terribly exhausted by morning. Sleep studies can help to tease out these complex relationships and thus shed light on what’s happening with your rest.

Can I Do A Sleep Study At Home?

Image credit: AASMNET.org

Much of this article was written with in-lab testing in mind, but let’s spend a little time talking about unattended testing as well. While not initially popular, home testing is now becoming more widespread. Back in 2007, the American Academy of Sleep Medicine (AASM) released clinical guidelines that prescribed under what conditions home testing could be used (for clarity, home testing is also referred to as ‘unattended portable monitoring’). Long and short of it, there isn’t enough conclusive evidence to show that home testing (PM), while less expensive, is functionally equivalent to in-lab polysomnography (PSG). You should be aware that PM does not collect all of the information collected via a standard PSG, and thus will only be used if there is a major likelihood that the you may have obstructive sleep apnea.

My wife’s test was done at home (since based on the questionnaire, her symptoms matched?the majority of indicators of OSA)–she was fitted with a portable sleep monitor that primarily collected information related to her blood pressure, respiratory effort, oxygen saturation and airflow. The PM apparatus recorded all readings to?an SD card which the pulmonologist then utilised with a 3rd party application for interpretation and analysis. After?a week, we sat with the doctor for approximately one (1)?hour?during which time he elaborated heavily on the results of the test. It was quite enlightening, not to mention encouraging. Before, we never thought we’d find a solution. But now there was hope!

As promising as home-tests are, it’s important to verify your eligibility for?one. The best thing is that many insurance providers now support this form of?diagnostic test, and Medicare and Medicaid will also cover them. The following criteria are usually used to judge eligibility:

  • Sleep evaluation points to high risk of moderate/severe sleep apnea
  • Patient’s age is between 18 and 65
  • You have no other sleep disorders (since these may interfere with results)
  • You are unable (due to health or other extenuating circumstances) to attend an in-lab study

And there you have it! I hope this helps to clear up some of the uncertainty associated with taking a sleep study. If you’re thinking about getting one, or if you’d like to share your experience, please drop me a comment below. I’d love to be able hear your views.

Sleep well until next time!




  1. Cody@FreedomCompounded

    Hey there Thomas,

    I’m amazed at how this worked out..but I’m actually schedule for a sleep study and I wanted to research about it so I know what I’m going into! Your page cleared my mind and broken down the sections that I was concerned about, especially the “How do I prepare” and “What happens during the study” sections. You’ve compiled all the research I needed into one place! Thank you so much!

    1. Joshua (Post author)

      I’m so glad I could help Cody! Do stop by again and let me know how your experience went. Take care!

  2. corrie95

    I really like all this information on sleep studies. I found everything I needed to know all on one page. I would love to recommend this website to people I know who need information on sleep studies since it could be quite scary not knowing what your getting into. this website can help ease someone’s worries when they get one.

    1. Joshua (Post author)

      Glad you liked it Corrie! I wrote this based on the anxiety this caused both wife and I. Just hoping to give someone else out there some hope and encouragement.

  3. Jackie

    Wow, great in-depth article! My brother just had a sleep study done because he snores badly. His doctor was concerned he had sleep apnea. The study changed is life. He left the clinic with a sleep monitor and a bunch of suggestions from his doc. As a result, his sleeping improved, he lost weight and developed better lifestyle habits (like going to bed earlier). Thanks for the post. really great info!

    1. Joshua (Post author)

      I am very heartened to hear about your brother’s improvement, Jackie! I hope he keeps up the good habits–they’ll be key to him breathing better, and thus sleeping better as well.


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