Sleep Testing FAQ

Sleep Testing

What should I expect when I go to a sleep lab?

If you have been diagnosed with a sleep problem or disorder, your primary care physician may refer you to a sleep lab or clinic where you will participate in a sleep study. A sleep study (also called a polysomnogram) is a test that records your physical state during various stages of sleep and wakefulness. It provides data that are essential in evaluating sleep and sleep-related complaints, such as identifying sleep stages, body position, blood oxygen levels, respiratory events, muscle tone, heart rate, amount of snoring and general sleep behavior. Usually you will make an appointment for your visit, which will take place at night. The sleep center may send you forms requesting your medical and sleep history prior to your appointment with the doctor. The form may ask for your bed partner's responses to some of these questions, since you may not be aware that you snore, stop breathing (sleep apnea) or kick your legs when you sleep. It also may provide tips and some special instructions for your sleep test.

Before your sleep test, you may meet with a physician or sleep specialist, who will go over your medical and sleep history. You may participate in a "split-night" test, in which half the night will be used to diagnose your sleep problem, and the other half will be used to treat the problem. This is sometimes done with patients who are being tested for sleep apnea.

After your arrive at the sleep center, you may be asked to complete a questionnaire on your sleep the night before. Many sleep centers offer a video or other information about the sleep study or specific disorders such as sleep apnea, since a significant percentage of those who have sleep tests are suspected to have sleep apnea. The video may also address what you should expect during the sleep test to ease any fears that you may have. Then you will be asked to change into nightclothes.

After changing, someone called a polysomographic technician will connect you to the electrodes that will record your brain waves and muscle movements throughout the night. The electrodes are placed in specific areas and applied with water-soluble glue and tape. The electrodes record brain waves, muscle movement, rapid eye movement (REM), air intake, and periodic limb movement. A microphone attached to your neck records snoring, and two belt-like straps around the chest and lower abdomen monitor muscle movement during breathing. Despite all of the equipment, most people say it doesn't disrupt their sleep.

After settling into bed, your technician may go to a monitoring room and ask you over an intercom to perform certain tasks that will show the electrodes are recording properly. You will be observed on a television monitor during the night, but that is to allow the technician to note your body movements during sleep.

When everything is working properly, the lights will be turned off and you can go to sleep. Many patients are so chronically tired that they have no problem falling asleep. While you are sleeping, your brain waves will be recorded to determine when you are awake or in Stage 1, 2, 3, 4 or REM sleep. You will be awakened in the morning and the electrodes will be removed. Since they are applied with water-soluble glue or tape, removal isn't painful. You will need to make an appointment with a sleep specialist to review the results of your study. You might be asked to complete a questionnaire concerning your sleep the previous night, and then you can go home.

Based on the results of your sleep study, you may be given treatment for a specific sleep disorder. For example, patients with sleep apnea may be prescribed Continuous Positive Airway Pressure or CPAP, which is a device that gently blows air into your nasal passages to keep the airway open while you are asleep.


What should I bring along when I participate in a sleep test?

  • Nightgown, pajamas, or any comfortable sleep wear, preferably with a button-down front
  • Your favorite pillow or blanket. Sleep centers provide bedding including sheets, blankets, and pillows, but yours may help you sleep better.
  • Toiletries such as a toothbrush, toothpaste, hairbrush, or comb
  • Clothes for the following day
  • Any needed medications.
  • A book or other reading material.


Do I need to do anything special before the test?

  1. Wash and dry your hair on the day of your sleep test. Try not to use any hair products, such as gels, hairsprays or heavy conditioners, because it may prevent the electrodes from sticking to your scalp.
  2. Remove nail polish and/or artificial nails from at least two fingers. The oximeter that is placed on your finger to monitor blood oxygen levels reads this information through the nail, so any polish or acrylic will not provide an accurate reading.
  3. Do not wear make-up. Some electrodes are on the face, so this area must be clean in order to get a good connection.
  4. Generally, you are asked to obtain a normal night's sleep before the test, unless instructed otherwise by your doctor. Continue to take your regular medications and limit caffeine intake the day of your test.