A UAB St. Vincent’s pulmonologist offers insight about what really happens during a sleep study and why it is worth doing.The idea of sleeping in a hospital, attached to wires while a care team monitors the whole thing, can feel intimidating. But Neal Daniel, M.D., a pulmonologist at UAB St. Vincent’s, helps put patients at ease and offers insight about what really happens during a sleep study and why it is worth doing.

What is a sleep study?

A sleep study, also known as a polysomnogram, is a diagnostic test that monitors various body functions while a person is asleep. It is most commonly used to diagnose sleep apnea but can also detect other conditions such as movement disorders, seizure activity, parasomnias (abnormal behaviors during sleep) and narcolepsy.

According to Daniel, the biggest misconception patients have is that they need a full night’s sleep for the study to work.

“We don’t expect anybody to have their best night of sleep ever in the lab,” Daniel said. “The goal isn’t perfection. It’s simply to get enough sleep data to evaluate your condition. Even a few hours of rest can be enough for us to understand what may be disrupting your sleep on a regular basis.”

What is being monitored

In addition to a patient’s breathing, there are a number of systems that are monitored during a sleep study, from which a lot of health information can be gleaned.

• Brain activity (EEG): Helps determine sleep stages and can detect seizures.
• Eye movement and jaw muscle tone: Aids in identifying REM sleep and issues like teeth grinding.
• Heart activity (EKG): Tracks rhythm and rate, screening for issues like arrhythmias or atrial fibrillation.
• Breathing: Airflow at the mouth and nose, chest and abdominal movement — all used to detect sleep-disordered breathing like obstructive sleep apnea.
• Leg movements: Looks for issues like periodic limb movement disorder.
• Snoring and body position: Captured via discreet video monitoring to contextualize data.
• Dream enactment behavior: The video feed helps capture behaviors associated with parasomnias, which can indicate underlying neurological conditions.

Sleep environment

A sleep lab is designed to be as comfortable as possible. Patients have a private room with its own bathroom, similar to the feel of a hotel. If a patient needs to get up in the night, a technician can quickly disconnect the monitoring unit so patients can move around without removing all the wires.

Most labs ask patients to arrive around 8 p.m., with lights out around 10 p.m., depending on individual bedtime routines. The study typically ends around 5:30 or 6 a.m., allowing time to shower and head to work if needed.

Before the appointment, someone from the sleep lab will usually call to confirm details and answer any last-minute questions. Patients are advised to take their usual medications, including sleep aids if prescribed.

If someone works nights, sleep labs can accommodate daytime studies for shift workers to mirror their regular schedules as closely as possible.

A sleep apnea diagnosis

“Snoring is often a symptom of sleep apnea, but not always,” Daniel said. “If you also experience daytime sleepiness or someone witnesses you gasping or pausing in your breathing while asleep, that’s a strong indicator that a sleep study is warranted.”

Continuous positive airway pressure, or CPAP, machines are commonly prescribed for those diagnosed with sleep apnea. And while the thought of being hooked up to a machine at night seems less than ideal, Daniel urges people to keep an open mind.

“It’s a non-medication treatment with virtually no side effects and a lot of potential benefits —better sleep, improved mood and energy, and for some patients, it may even lower blood pressure,” he said. “While there is some adjusting, once you get over that hump, most people feel so much better that they wouldn’t let me take it away from them if I tried.”

Some people have struggled with sleep-related issues and put off a sleep study, so Daniel hopes patients understand that the process is designed to be as smooth and informative as possible.

“I tell patients, what you need when you’re going to the sleep lab for the first time is an open mind — to the study itself and then to CPAP if that’s what you need. Because it can really help you,” Daniel said.