How to Prepare for an Overnight Sleep Study

Before you go

An overnight sleep study can feel easier to prepare for once you know what the center needs from you. There is usually an arrival time, a list of things to bring and a plan for the next morning. Read the instructions when you receive them so you can ask questions before the day of the test.

This guide covers an overnight study at a sleep center, often called polysomnography. Mayo Clinic explains that the test records several signals while you sleep, including breathing, heart rhythm, brain activity and blood oxygen. Home sleep apnea tests use a different setup, so check which kind your clinician ordered before making plans.

If the instructions are missing or unclear, call the center. Confirm where to check in, whether you can eat dinner beforehand and when you can expect to leave. Let the staff know ahead of time if you need help getting into bed or moving around the room.

For a related guide, read Morning Light and Your Sleep-Wake Routine: Practical Ways to Begin.

Ask about medicines and your usual routine

Make a list of your prescription medicines, over-the-counter products and supplements. Ask the clinician or sleep center which ones to take and when, especially if you regularly use something to help you sleep. Have the name and usual timing handy so the team can answer for the specific product. Follow their guidance before making any change.

Mayo Clinic advises avoiding alcohol and caffeine during the afternoon and evening before the study and skipping an afternoon nap. Check what your center asks you to do, particularly if you work nights or normally sleep during the day. It is easier to carry out those instructions when you plan your afternoon around them.

Pack for one night and the morning after

Bring comfortable sleep clothes and the toiletries you need. If you usually sleep with a particular pillow or another familiar item, ask the center whether you can bring it. Confirm whether the center supplies towels and bedding if that affects what you pack. Put the center’s phone number and check-in location somewhere you can find them easily.

Mayo Clinic suggests washing your hair before the test and avoiding products that can interfere with sensors. Leave hair gel and spray off unless the center gives you different instructions. If you use a positive airway pressure machine or another device at night, ask whether to bring it and which parts the staff need.

Know what happens when the sensors go on

A technologist attaches sensors to areas such as the scalp, face, chest and legs. The sensors measure changes while you sleep. You may also have a small clip on a finger to track blood oxygen. Mayo Clinic notes that wires are long enough to let you move in bed. Tell the technologist if something pinches or pulls before they turn out the lights.

Ask how to call for help if you need to get up during the night. The staff can help with the wires so you can use the bathroom. If you are worried you will sleep less than usual in an unfamiliar room, mention it during check-in. Mayo Clinic notes that less sleep than usual generally does not affect the results.

For a related guide, read Restless Legs at Night: What to Notice and Tell Your Clinician.

Confirm how you will get the results

The sensors come off before you leave. Ask who will review the recordings, when you should expect to hear from them and whether you need to book a follow-up appointment. The technologist collecting the data overnight may be a different person from the clinician who interprets it.

If your night felt unusual, make a short note before you forget. Write down anything you want to mention at follow-up, such as trouble settling in, a bathroom trip or whether you woke earlier than normal. Bring your questions about the findings and what they mean for the sleep concerns that led to the study.