A polysomnography, commonly known as a sleep study, is a non-invasive test used to diagnose sleep disorders like sleep apnea, narcolepsy, and restless legs syndrome. This overnight examination monitors various physiological functions, including brain waves, heart rate, breathing, and muscle activity, while a person sleeps. To gather accurate data, the sleep environment and the patient’s routine must be carefully controlled, which is why there are specific rules regarding activities like watching television.
The Direct Answer: TV Use Before and During Monitoring
The general rule is that you can often watch television or engage in other low-key activities before the formal monitoring begins. Sleep center rooms are typically private and designed to be comfortable, sometimes including a television for relaxation. This period allows you to settle in and maintain a semblance of your normal evening routine before the sleep technologist begins attaching the numerous sensors and electrodes.
However, once the equipment setup is complete and the technologist prepares for “lights out,” all electronic devices, including the television, must be turned off. Introducing the stimulation of a television screen after the hookup would interfere with the natural onset of sleep and compromise the data collection. Therefore, viewing is strictly prohibited once the study is underway.
General Rules for Preparing for a Sleep Study
Beyond television, several other restrictions are in place on the day of your study to prevent external factors from skewing the results. It is generally recommended to avoid consuming caffeine, including coffee, tea, chocolate, and colas, for at least 8 to 12 hours before the study begins. Similarly, all forms of alcohol should be avoided entirely on the day of the test, as both substances can disrupt the natural sleep architecture and mask underlying issues.
Patients are also usually instructed to avoid napping during the day of the study to ensure sufficient sleep drive at night. Before arriving, you will need to shower and wash your hair, but you must refrain from using products that prevent the electrodes from securely adhering to the skin and scalp. Any regular prescription or over-the-counter medications should be discussed with your physician beforehand, but generally, you should continue taking them unless otherwise instructed.
Hygiene Restrictions
These products include:
- Hair sprays
- Gels
- Oils
- Lotions
How Screens Affect Sleep Study Results
The primary reason for prohibiting screens like television, phones, and tablets during the monitoring phase is their physiological impact on the sleep cycle. Electronic screens emit blue wavelength light, which is particularly effective at suppressing the production of the hormone melatonin. Melatonin is naturally released as light levels dim and is important for signaling to the brain that it is time to sleep.
Exposure to this light keeps the brain in an alert state, delaying the time it takes to fall asleep, a metric known as sleep latency. Furthermore, the stimulating content often consumed on these devices, such as news or engaging shows, increases cognitive arousal.
This heightened brain activity is reflected in the electroencephalogram (EEG) readings, which can make it difficult for the technologist to accurately identify the transition into deeper, more restorative sleep stages. If a person takes significantly longer to fall asleep, the study may not capture the necessary periods of rapid-eye-movement (REM) or slow-wave sleep. Since the diagnosis of many sleep disorders relies on observing specific physiological events during these deeper stages, skewed data could lead to an inaccurate or inconclusive result.