What Happens During a Sleep Study?

During a sleep study, you spend the night in a private room at a sleep lab. Small sensors on your skin track your sleep stages, breathing, and vital signs while you sleep. The test is painless and non-invasive, and most patients find it much easier than expected.

How should you get ready?

If your doctor has recommended a sleep study, you might feel nervous about what to expect. That's completely normal. Many patients tell me they were surprised at how simple and comfortable it turned out to be. Before you arrive:

• Medicines — Follow your doctor's instructions about medications. Some may need to be adjusted.
• Caffeine and alcohol — Avoid them on the day of your study.
• Skin and hair — Shower and wash your hair, but avoid hair products, lotions, or nail polish.
• What to pack — Comfortable sleepwear, toiletries, and anything you need for your bedtime routine.
• Your medicines — Bring any medications you take at night or in the morning.

What happens when you arrive?

You'll typically arrive at the sleep lab between 7:30 and 9:00 PM. The sleep technologist will greet you and show you to your private room. You'll have time to change and settle in. Sleep lab rooms are designed to be comfortable, with a regular bed, television, and private bathroom.

Next, the technologist will put several small sensors on you to monitor your body during sleep. This setup takes about 30-45 minutes. The sensors measure:

• Brain waves (EEG) — Sensors on your scalp track sleep stages
• Eye movements (EOG) — Sensors near your eyes detect REM sleep (the dreaming stage)
• Muscle activity (EMG) — Sensors on your chin and legs monitor movement
• Heart rhythm (ECG) — Sensors on your chest track your heart rate
• Breathing effort — Elastic belts around your chest and belly measure breathing movements
• Airflow — A small sensor near your nose and mouth detects air movement
• Oxygen levels — A clip on your finger measures the oxygen level in your blood
• Snoring — A microphone on your neck records how loud you snore

What happens during the night?

Once everything is set up, the technologist will turn off the lights. They monitor you from a nearby control room. You can sleep in any position that's comfortable. If you need to use the bathroom or adjust anything during the night, just speak up. The technologist can hear you through an intercom.

In some cases, a split-night study may be done. If significant sleep apnea is found in the first half of the night, the technologist may wake you. They fit a CPAP mask and find the right pressure setting during the second half.

Many people worry they won't be able to sleep with all those wires. Most patients are surprised that they sleep better than expected. The sensors are designed to stay out of the way, and you can move freely during the night.

What happens in the morning?

You'll be woken up around 6:00 AM. The technologist will remove all sensors, and you'll have time to shower and get ready for your day. Leaving is quick. Most patients are out the door within 30 minutes.

How do you get your results?

A board-certified sleep medicine physician will review the data from your study. This includes your sleep stages, breathing events, oxygen levels, and heart rhythm. You'll go over your results at a follow-up appointment. Ask our office when to expect them.

Your doctor will explain your Apnea-Hypopnea Index (AHI), the number of breathing events per hour. They will discuss treatment options based on your diagnosis. A sleep study is the most important step toward diagnosing and treating sleep disorders.

What types of sleep studies are there?

• Diagnostic polysomnography — Monitors sleep to diagnose disorders
• CPAP titration study — Finds the right CPAP pressure setting
• Split-night study — Diagnoses sleep apnea and sets CPAP pressure (titrates) in one night
• MSLT (Multiple Sleep Latency Test) — Daytime nap test for narcolepsy
• Home sleep apnea test — Simpler testing done at home