Sleep Study FAQ

El Camino Health's sleep experts use sleep studies (polysomnography) to diagnose sleep disorders. Knowing what to expect can help you prepare.

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For many sleep disorders, the best method of diagnosis is the sleep study, also called polysomnography. At El Camino Health, sleep studies are performed overnight in our sleep lab, which is accredited by the American Academy of Sleep Medicine. Your results are then analyzed by sleep experts, who will discuss your condition with you and recommend treatment.


How do I schedule my sleep study appointment?

If your doctor recommends a sleep study, the El Camino Health Sleep Center coordinator will call you to schedule your appointment. You’ll also get a call from our patient registration representative, who will pre-register you over the phone.

How should I prepare for my sleep study?

In general, you should follow your normal schedule before your sleep study. Eat meals at the normal time and go to bed when you usually do.

Additionally, follow these specific instructions:

  • Avoid alcohol and caffeine for at least 24 hours before your study.
  • Don’t take naps the day before.
  • Shower and wash your hair before the study, but please arrive with dry hair. Wet hair can affect the monitoring signals.
  • Don’t apply any makeup, lotion, powders, hair conditioner, hairspray or gel, or silk or gel fingernails. These products can interfere with the measurements taken through the electrodes.
  • Tell your doctor about any medications you’re taking, including over-the-counter medications and supplements, which can alter test results.
  • Unless your doctor tells you otherwise, don’t take any sedatives (sleep aids) before your test. People who typically use a sedative may need to continue in order to sleep adequately during the study.

You can bring your own pajamas and pillow to the study. Please leave any jewelry at home, since it can interfere with the measurements.

Where do I go for my sleep study?

Plan to arrive 15 minutes prior to your sleep study appointment. Upon arrival, call the Sleep Tech by dialing 408-866-4071. The Sleep Tech will meet you at the front door and will then escort you to the sleep room.


Sleep Study Directions


Whom can I contact if I have additional questions or I need to change my appointment?

Call the El Camino Health Sleep Center coordinator at 408-866-4070 between 8:30 a.m. and 5 p.m. Monday through Friday. If you need to contact us after hours or need to change your appointment the night before it’s scheduled, call the sleep technician at 408-866-4071 after 7 p.m. Monday through Friday . He or she can also give you directions to the sleep center and meet you when you arrive.

What happens during a sleep study?

You’ll arrive early in the evening for your sleep study — your doctor will tell you the exact time. It’s a good idea to bring a book or something else to occupy you while you await the start of your study.

After you change into your pajamas or a hospital gown, a technician will attach a number of small discs, called electrodes, on your head and body with gel or adhesive. The electrodes are connected by wires to a computer, but the wires are long enough to allow you to move normally in bed. The technician will also place a small clip on your finger or ear to monitor the oxygen level in your blood. If you’re having a CPAP (continuous positive airway pressure) study, he or she will help you choose a comfortable mask to wear.

When your technician is ready to start the test, you’ll try to go to sleep as you would normally at home. In the morning, the electrodes and other devices will be removed. Before you leave, we’ll provide you with a free, continental breakfast.

What if I need to use the bathroom during the night?

If you need to get up and use the bathroom during the night, it’s a simple and convenient process. Simply notify the technician, and he or she will unplug the wires and reconnect them when you return.

What does a sleep study measure?

The electrodes and other devices send information to instruments in a central monitoring area where a technician can observe the data. Sleep studies also use video cameras to record your movements during sleep. These instruments record measurements such as:

  • Eye movement and brain activity.
  • Number and intensity of limb movements.
  • Breathing patterns, including shallow breathing or apnea — episodes of stopped breathing.
  • Heart rate and rhythm.
  • Level of oxygen in your blood (oxygen saturation).
  • The time it takes for you to fall asleep (sleep latency) and how long you stay asleep (sleep duration).
  • The ratio of your total time asleep to the time you’re in bed (sleep efficiency).
  • Episodes of lighter sleep stages or awakening, associated with breathing changes or limb movements (arousals).
  • Stages of sleep, such as REM, non-REM and slow-wave sleep.

Are there any risks involved with a sleep study?

The only known risk during a sleep study is a possible skin irritation from the gel or adhesive used to place the electrodes on your skin. Tell your doctor or the sleep study technician if you have sensitive skin.

Are sleep studies always done at night?

Sleep studies are done during the time people typically sleep, which is usually at night. For shift workers and others with unusual sleep schedules, the test can be done during the day.

What happens after the study?

A sleep medicine doctor analyzes the test results, along with information from your medical history and any other tests, to arrive at a diagnosis. You’ll have follow-up appointments with one or more sleep specialists to discuss your condition and treatments:

  • If your treatment involves using equipment, such as a CPAP device, you may work with a respiratory therapist to get fitted for the device and learn how to use it.
  • If your treatment options include a dental device or surgery, you’ll be referred to a sleep surgeon or a dentist who specializes in dental sleep medicine.

El Camino Health’s sleep specialists also coach people on healthy sleep habits that can help on their own or in combination with other treatments. Your sleep care team will keep your primary care doctor and/or referring doctor informed about your diagnosis and treatment plan to assure care continuity.