What You Should Know About Sleep Tests

The sleep study, or polysomnography, is a test that records your body’s movement and electrical activity when you’re sleeping. It also measures the oxygen level in your blood and the amount of carbon dioxide in your lungs to screen for problems such as sleep apnea.

The test results help determine if treatment is needed, what kind of treatment should be used, and if surgery is required. Doctors usually order a sleep study if you have sleep disorder symptoms or abnormal movement during sleep. Sleep testing is done to diagnose or monitor health problems suspected to be related to inadequate sleep.

What is a sleep study?

A polysomnogram is an in-lab test that records information about your natural sleep cycles. The data is used to diagnose your sleep patterns and determine whether you have any obstructive sleep apnea or other condition that may be affecting your quality of sleep.

The most common type of test is an in-lab overnight test. To ensure the best results, you need to stay awake during the day and only sleep 8 hours before you come in for the test at night. You can eat whatever you like during this time, including your favorite foods and drinks, but try to avoid caffeinated beverages as they tend to stay in your system for a long time.

Who should have a sleep test?

If you snore while sleeping or you feel extremely sleepy during the day, a sleep study may help determine whether you have a severe disorder affecting your sleep quality. A snoring dentist will help to decide whether or not you need a sleep test. Here are some symptoms of a sleep disorder:

· Excessive daytime drowsiness.

· Difficulty staying awake while at work, drowsy driving, or getting into accidents due to drowsiness.

· Difficulty concentrating on tasks.

· Inability to complete tasks or disorientation from lack of sleep.

· Falling asleep unintentionally during the day.

· More than 3-5 episodes a week of leg cramps in the calf, foot, and toe.

· Frequent waking up at night and having trouble falling back asleep.

· A change in:

· Your bedtime or wake time is more than 1 hour.

· Your sleep quality, patterns, timing, or amount of sleep.

Where is a sleep test done, and what should you expect?

The sleep study is usually done in a hospital or laboratory and may last a night. During the test, you are watched by staff, and several measurements are recorded. You will sleep overnight in a private, quiet room with video and audio recording equipment nearby. Staff members will keep watch on you the whole time.

The staff also checks the equipment during regular study breaks to make sure it is working correctly. A technician may adjust some of the measurements depending on how restless or noisy the patient is at night. During the study, you will wear a small detector that picks up signals from different parts of the body. The signals are recorded on graph paper or computer printouts. They show how much time you spend in different sleep stages during the night.

A technologist who specializes in sleep medicine will look over the study results to see if there are problems with your sleep. The technologist will also look at other medical information that may be available. It would help if you had a regular bedtime routine for several days before the test.

The technologist will explain to you what to expect during the test. It would help if you did not do any strenuous activities during the several hours before the test. Before the test, regular feeding is allowed, but you might be asked to take a mild sedative before sleeping. Consult the technologist before taking any medication.

Screens and machines around the bed show pictures and waveforms that tell how well air moves in and out of your lungs during the test. Other screens show your breathing and heartbeat, whether you are snoring, if your muscles are twitching in sleep, how much oxygen in the blood is dropping with each breath (oxygen desaturation), and how fast you are sleeping.


Sleep test results will help show how long it takes for you to fall asleep, how frequently you wake up during the night, and the number of times you stop breathing. It also shows whether there are any pauses in your breathing during sleep. Interestingly, doctors can use this information to determine your risk of developing cardiovascular problems later on in life. Your sleep doctor will use the results to recommend treatment.

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