What Happens During A Sleep Study?


If you suffer from a sleep disorder of any kind, then your doctor may recommend that you undergo a sleep study. What does this entail, and what can you expect? Is it scary or complicated? What can you gain from it?

We’re here to answer all those questions and more, so you can get the treatment you need with peace of mind.

Let’s dive in.

What is a Sleep Study?

Sleep studies are simple, non-invasive exams that let your doctors monitor you while you sleep. This allows them to see what’s going on in your brain and body during this time.

Usually, these studies are performed overnight at sleep clinics, which are specialized sleep centers that can be either inside the hospital or their own facility elsewhere. The rooms in these clinics are set up to be as comfortable for you as possible, so your doctors can get the most authentic and accurate results.

sleep center

They will then monitor you all throughout the night via cameras set up in the room and sensors attached to your body, which measure vital signs like your heart rate and breathing. The sleep specialists in this facility can also help you out of these sensors if you need to use the bathroom in the middle of the study.

If you’re particularly anxious about having others watch you sleep, then rest assured that your doctors will not need you to sleep the whole night in order to get the information they need for this study.

Other than helping your doctors properly diagnose any possible sleeping disorders, sleep studies can also be used to figure out how to adjust your current sleep disorder treatment plan.

Types of Sleep Studies

There are 4 different types of sleep studies.

Diagnostic Overnight Polysomnogram

The most common study performed is the diagnostic overnight polysomnogram (or PSG, for short). This is when your doctors measure various body functions while you sleep, including breathing patterns, oxygen levels in your blood, heart rate, and eye and limb movements.

Diagnostic Daytime Multiple Sleep Latency Test (MSLT)

Doctors use the diagnostic daytime multiple sleep latency test (or MSLT, for short) to diagnose narcolepsy. This is done by measuring how quickly you fall asleep during the day, as well as how quickly and how often you enter REM sleep during these periods.

Usually, doctors will perform this test the morning after you undergo a diagnostic overnight PSG.

sleep study

Two-Night Evaluation Polysomnogram And CPAP Titration

This test can help doctors diagnose whether or not you suffer from sleep apnea.

On the first night, you will undergo a regular diagnostic overnight PSG. If your doctors find that you do, in fact, have sleep apnea, they will invite you to come back another night to determine the right air pressure for your CPAP (or continuous positive airway pressure) machine.

These machines have a specially-designed nasal mask for you to wear throughout the night, which can help you breathe better at night.

Split-Night Polysomnogram With CPAP Titration

A split-night PSG with CPAP titration is, essentially, the same procedure as the two-night evaluation polysomnogram. The only difference is that, if your doctors find that you have moderate or especially severe sleep apnea during the PSG, they will increase the strength at which the CPAP machine will work.

Home Studies

Depending on where you live and the disorders your physician wants to confirm, you may even perform your own sleep study at home. Of course, you still need to drop by a sleep clinic for the proper equipment.

what is a sleep study

Your sleep technician should then teach you how to apply and remove the sensors you need to wear throughout the night, as well as how to use the sleep screening device that will record your bodily functions. These sensors will typically include one or two chest belts, a nasal cannula, an oximeter, and the accompanying recording device.

This option can be especially beneficial to those who are anxious about their doctors watching them sleep. You also get the added bonus of feeling comfortable in your own home. The next morning, you can simply remove the sensors yourself and return everything back to the sleep center, so your doctor can study the results.

Why Might You Need a Sleep Study?

The results of a sleep study can help your doctor properly diagnose sleep disorders, including:

  • Sleep-related breathing disorders, like sleep apnea.
  • Sleep-related seizure disorders.
  • Sleep-related movement disorders, such as periodic limb movement disorder or restless legs syndrome.
  • Insomnia.
  • Sleep disorders like narcolepsy, shift work sleep disorder, or circadian rhythm sleep disorders that cause extreme exhaustion during the daytime.
  • Problematic nighttime behaviors, like sleepwalking, night terrors, or bed-wetting.
  • Teeth grinding during sleep (also known as bruxism).
  • REM sleep behavior disorders, which are sleep disorders that can interfere with the different stages of sleep. You undergo at least four to five cycles of non-rapid eye movement (or NREM) sleep to rapid eye movement sleep (or REM) sleep every night, and any disruptions to this cycle can create problems.

How Does a Sleep Study Work?

Sleep studies aren’t as complicated as they might sound! In fact, the hardest part for you may be actually falling asleep in the facility.

The sleep technicians are there to make you feel as comfortable as possible, so try to take it easy and relax; they are there to help you figure out how to cope with your sleep disorders.

What Does a Sleep Study Show?

As stated above, PSGs record your vital signs and any odd eye or limb movements associated with certain sleep disorders. These recordings can help your doctor better determine what sleep disorder you are suffering from, if any at all.

If you are being studied because you suffer from sleep apnea, then the technicians at the laboratory will also measure your sleep apnea “score”. This score is referred to as the apnea-hypopnea index, or AHI for short. It measures the number of times you suddenly stop breathing (a condition called apnea) and the times your breathing is abnormally slow or shallow (a condition called hypopnea) during this study.

what does a sleep study show

All this data will give your doctors a better picture of your sleep patterns, including roughly how long you spend in each sleep stage, whether you are getting enough oxygen, how many times you wake up (no matter how temporarily), and other factors that may be disturbing your sleep. Your doctor may take up to two weeks to evaluate the data and schedule a follow-up appointment to discuss the results with you.

What to Expect at a Sleep Study

Usually, the sleep technicians will advise you to arrive at the sleep center at least two hours before your regular bedtime. You are allowed to bring any personal items that help you sleep better at night and you can wear your own pajamas, instead of a breezy hospital gown.

Most patients arrive are anywhere between 8 and 10 p.m. and sleep for around seven to nine hours at the clinic. Most sleep clinics only need around seven hours of sleep time to study, but they will not disturb or wake you up if you want to sleep longer.

The Rooms

The clinic’s rooms are set up more like hotel rooms than the typical areas you might find at hospitals. If you need any help during the night, the sleep technicians will always be right next door to your room. There are also video cameras in the room, so they can check in on you every now and then while you sleep.

how does a sleep study work

Sleep Study Equipment

Before you go to sleep, the sleep technicians will hook up sensors to your head and body. The wires that connect the sensors to the recording machines are loose enough to allow you to move around in your sleep freely, and, in fact, most people find themselves getting used to it fairly quickly.

You may also have elastic belts wrapped around your chest and abdomen to measure your breathing, with a small clip gently clamped around your index finger to monitor the oxygen levels in your bloodstream. If you’re coming back for a second night to measure your sleep apnea, the technicians will also connect you to a CPAP machine.

How to Get the Most Out of the Sleep Study

Avoid taking any naps during the day of your sleep study, if at all possible.

It’s also best to avoid certain stressors, including ingesting any alcohol or caffeine beforehand, and tell the technicians about what medications and supplements you are currently taking.

The sleep technicians do not expect you to sleep as good as you would at home (unless you have the chance to do the study in your own home), though most patients are surprised to find that they sleep better than they expect to.

Again, if you need to use the bathroom in the middle of the study, you can simply alert your technician via the cameras in the room. They will disconnect the wires for you and help you put them back on whenever you’re ready.

Where to Find a Sleep Study Clinic

There are several types of doctors who are qualified to order a sleep study for you, including:

  • Your primary care physician, or the doctor that you first see whenever you feel ill.
  • A sleep specialist, who are board-certified doctors that can properly diagnose you with sleep disorders, more-so than your primary care doctor.
  • Neurologists, or doctors who treat disorders that can affect your brain, spinal cord, and/or nerves.
  • Psychiatrists, or doctors who specialize in diagnosing and treating mental illnesses.

Typically, your primary care doctor will already know of a sleep clinic attached to your healthcare program or a trustworthy sleep study facility nearby, so they may recommend one of those.

sleep clinic

You may also use this handy finder tool to locate a sleep center near you. Just input your full address, your city, state, or zip code, and adjust the search radius to include the distance you’re willing to travel.

Price Ranges

Most health insurance plans will cover stays at sleep clinics, though it’s always best to check with your provider beforehand. Depending on the type of sleep study you undergo, where you take it, and your insurance plan, a single sleep study can cost anywhere between $500 to $3,000.

However, if the clinic is with an in-network provider and you’ve met your deductible, then you may only have to pay anywhere between $0 to $150 for this visit.

Sleep studies that take place outside of your network (or in-home kits) can cost you anywhere between $300 to $600. If your insurance covers it and you have met your deductible, then you will only pay an out-of-pocket cost of anywhere between $0 to $50.

The rate you end up paying for the study will depend on your health insurance company. Before you undergo a sleep study, be sure to check how much of it will be covered by insurance and how much you’ll need to pay out-of-pocket for the procedure.

Try to find a sleep clinic that is within your contracted or in-network provider, rather than one who will accept your insurance but isn’t contracted. The in-network coverage could pay for up to 80 to 100 percent of the cost of the procedure, while out-of-network coverage may only cover 50 percent to none at all, depending on whether you have met your deductible or not.

Deductibles can be as high as $2,000 to $4,000, or even more. Even if you have coverage for the service, you may still have to pay out-of-pocket until you meet that deductible.

Typically, patients who go to a sleep center in-network are charged a co-pay of around 20 percent, meaning that they will pay somewhere between $100 to $200 for the procedure.


If you’re nervous about undergoing a sleep study, there is no need to be! Just remember that these sleep technicians are there to help you treat any sleep disorders you may be suffering from. One night at a sleep clinic can make a huge difference in your ability to sleep healthily and comfortably.


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