Sleep Studies: What to Expect from Sleep Apnea Testing and Polysomnography

A sleep study helps healthcare providers investigate sleep disorders and plan treatment. An overnight study, called polysomnography, records brain activity, breathing, heart rate, blood oxygen levels, and movements while you sleep.

Testing may take place at a sleep center or, for selected patients, at home. The appropriate test depends on your symptoms, medical history and suspected condition.

When Might You Need a Sleep Study?

Your provider may recommend testing if you have symptoms such as loud snoring, witnessed pauses in breathing, excessive daytime sleepiness, or unusual movements and behaviors during sleep.

Sleep testing can help evaluate:

• Sleep apnea and other sleep-related breathing disorders.
• Periodic limb movement disorder.
• Certain unusual sleep behaviors, including acting out dreams.
• Narcolepsy and other causes of excessive sleepiness, using specialized testing.

Not every sleep problem requires an overnight study. Your provider will determine whether testing is appropriate, and which type will provide useful information.

Overnight Sleep Study vs. Home Sleep Apnea Test

In-Lab Polysomnography

An overnight study at a sleep center records multiple physiological functions and sleep stages. A technologist monitors the recording and can assist you throughout the night.

This more comprehensive test can evaluate breathing problems, certain movement disorders, and other sleep concerns.

Home Sleep Apnea Testing

A home sleep apnea test uses portable equipment to record breathing-related measurements while you sleep in your own bed. It records fewer signals than a full overnight study and is primarily used to evaluate suspected obstructive sleep apnea.

Home testing is appropriate for selected adults—not everyone—and must be ordered and interpreted by qualified healthcare professionals. It is not a substitute for testing for narcolepsy or other unrelated sleep disorders.

Testing for Narcolepsy

Narcolepsy evaluation often includes an overnight study followed by a multiple sleep latency test. This daytime test measures how quickly you fall asleep and your sleep patterns during scheduled naps.

How to Prepare for a Sleep Study

Follow the testing center’s specific instructions. These typically include:

• Avoiding alcohol and caffeine during the afternoon and evening before testing.
• Avoiding naps on the day of the study unless instructed otherwise.
• Keeping your usual sleep schedule.
• Avoiding lotions or hair products that could interfere with sensors.
• Bringing comfortable sleepwear and essential bedtime items.

Ask which medications to take; do not stop taking prescribed medication on your own.

What Happens During the Test?

For an in-lab study, sensors are attached to your scalp, face, chest, and legs. Breathing sensors and a blood oxygen monitor provide additional measurements. The sensors record information—they do not deliver electrical stimulation.

The study may track brain waves, eye movements, heart rhythm, airflow, breathing effort, oxygen levels, and muscle activity. Audio or video may also help document snoring and sleep behaviors.

If you do not sleep as well as usual, the study may still yield useful results. A full night’s sleep is not always necessary. Some studies also assess positive airway pressure (PAP) settings for sleep apnea treatment.

Results and Next Steps

A qualified provider reviews the recording and discusses the findings, treatment options or additional testing. Follow instructions for returning or disposing of home equipment.

A negative, inconclusive or technically inadequate home sleep apnea test may require follow-up polysomnography to evaluate suspected sleep apnea.

Get Help for Sleep Concerns

Persistent snoring, disrupted sleep, or daytime sleepiness warrants attention. Schedule a visit with tru Primary & Urgent Care to discuss your symptoms and determine whether sleep testing or a specialist referral is appropriate.