How Watching TV Before Bed Can Ruin Your Sleep

Television produces blue light and watching it before bed can ruin your sleep. Learn how turning off the TV an hour or more before bed can save your sleep.

By Sheryl Grassie

We are hearing more and more about how important sleep is to our health, and how important a bedtime ritual is to our sleep; same time to bed, lights off, fan on, and reading in bed with a book light. However, as much as 65% of the adult population watches TV as part of their nightly routine. Among people in the 13-29 year old category, 50% watch TV before bed. Overall, statistics estimate that 95% of the adult population is on some form of screen just prior to going to sleep.

Young woman relaxing in bed late at night and watching tv, she is holding a remote control

Many might argue that watching TV puts them to sleep. But even if you nod off while watching a favorite show, the screen has detrimental effects on sleep overall. The blue light emitted from the television screen affects the brain in two fundamental ways as it relates to sleep.

First, it stops the production of the sleep hormone melatonin, which then disrupts your circadian rhythm. Second, it delays the onset of REM sleep. There are additional cautions about watching TV before going to bed or falling asleep with it on. There are also serious possible side effects to health. Let’s take a deeper look.

Blue Light and the Brain

Not all light is created equal. Blue light has a more extreme effect on the brain in relation to sleep. The first thing it does is cause a decrease in melatonin, the sleep hormone. Melatonin makes us sleepy and helps us fall asleep. Blue light suppresses melatonin production three times more than incandescent light does. When you watch TV close to bedtime, your eyes take in the blue light and transfer it to the brain. When the brain registers this light, it stops producing melatonin.

A lack of Melatonin can completely change your biological clock, telling your body to wake up when it should be sleeping or making you tired during the day when you want to be awake. This change in your circadian rhythm can wreak havoc with your overall sleep schedule.

The other direct effect blue light has on the brain is that it postpones the body moving into REM sleep. We have essentially two principle sleep stages, non-rapid eye movement sleep (NREM) which is the light phase of sleep, and rapid eye movement sleep (REM) the deep phase of sleep. It is primarily in REM sleep that the body does its repair work.

The less time you spend in REM sleep, the fewer repairs to muscles and tissues, and the greater chance of disease. Being exposed to the blue light of TV keeps the brain during sleep in a longer non-repair state.

Cautions About TV Before Bed

In addition to changes to hormones and sleep patterns, watching TV just prior to bed can have other effects on sleep. If television content is too violent or emotionally charged, it can leave you anxious and unable to sleep, tossing and turning with insomnia. Many television series are formulated to encourage binge watching, and it is an easy trap to find yourself staying up way later than planned to watch just “one more episode.” This can challenge having a consistent bedtime.

Also, if you fall asleep with the television on, the volume can fluctuate and wake you at different points in the night, interrupting sleep. Research finds that people who watch TV in their bedrooms are essentially training their minds to perceive the bedroom as a place to relax and watch TV, but not necessarily as a place to sleep.

Good sleep hygiene suggests keeping the bedroom only for sleep and physical intimacy; no TV in the bedroom. Good sleep hygiene also suggests turning off the TV at least one hour, and preferably two hours, before bed. If you just can’t give it up, consider purchasing a blue light blocking screen.

Final Thoughts

Watching television before bed disrupts sleep and can cause sleep debt. Poor sleep equates to poor health. Watching TV before bed and being exposed to blue light is associated with increased obesity, higher levels of diabetes, and heart disease. Blue light lowers melatonin which has other jobs besides putting you to sleep, it repairs cells, and lowered levels are linked with some forms of cancer including breast cancer. Overall, it appears wise to stop watching TV before bed and find a different activity prior to sleeping.


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