New Research on Screen Time Explains Why It Sabotages Children’s Sleep

by ParentCo. November 23, 2017

boy looking at tv

Every now and then, especially on the weekend, it’s tempting to want to forgo the rigid bedtime routine in favor of the “movie night” your child is itching to have. After all, you figure, your preschooler’s exhausted – he’ll be asleep within five minutes. But then, without fail, you watch in horror as "Moana" not only captures his full attention for an hour-and-a-half, but he also begins bouncing from couch to couch belting out “How Far I’ll Go” and requesting another feature-length film, which would be fine and super fun if it wasn’t 10 p.m. Sound at all familiar? Recent studies have shown that children and adolescents are highly susceptible to sleep disruption from screen-based media use and exposure, far more so than adults. And an article published by the University of Colorado Boulder gets to the root of why. Authors at CU Boulder composed a comprehensive review of new literature published in the journal Pediatrics. The findings are quite eye opening (plenty of pun intended). The authors explain that children are more sensitive to light than adults, because their eyes are still developing. So light from digital media has a greater impact on their internal body clock. In one of the many studies reviewed on youth ages five to 17 from all over the world, researchers found that children’s melatonin levels fell twice as much as adults when exposed to the same amount and intensity of light.

Melatonin and sleep

So, what does that mean? Well, since melatonin is a hormone in the body that promotes sleep, suppressing it delays feelings of sleepiness, and also pushes back the timing of the body’s clock. Studies also show that short-wavelength "blue light" which emanates from hand-held electronics has an especially intense effect on melatonin, strongly suppressing it. “Through the young eyes of a child, exposure to a bright blue screen in the hours before bedtime is the perfect storm for both sleep and circadian disruption,” says the first author of the study, Monique LeBourgeois. But the sleep-disrupting effects of screen-time have more than biological and neurological underpinnings. Digital media in its various forms is also psychologically stimulating, say the authors of this sweeping review. Watching violent movie scenes or texting with friends can cause cognitive arousal, which is not, of course, conducive to falling sleep. Even just leaving a phone or computer on in the bedroom can hinder good sleep for kids and teens, and yet so many do it. Data shows that more than 75 percent of youths have screen-based media in their bedrooms, 60 percent interact with them in the hour before bedtime, and 45 percent use their phones as an alarm. Personally, I do all three and sometimes I even check or scroll through my phone when my baby wakes up to nurse during the night. I’ve noticed on the nights that I do reach for my phone that it’s harder for me to fall back to sleep. I can only imagine how much harder it would be for a young person jacked up on all that blue light and social media. Dr. Pam Hurst-Della Pietra, founder of the nonprofit Children and Screens says, "The digital media landscape is evolving so quickly, we need our research to catch up just to answer some basic questions.” One of those questions is how screen time impacts very young children whose mobile media device use has tripled since 2011. According to a recent report from Commensense Media shared by CU Boulder, children under eight use mobile media devices an average of 48 minutes per day and many parents incorporate digital media into the bedtime routine, leaving many experts wondering about the implications.

Sleep study

LeBourgeois points out, "The preschool years are a very sensitive time of development during which use of digital media is growing more and more pervasive. There's a lot we don't know." But she’s determined to learn more. This summer, LeBourgeois started a five-year, $2.5 million study funded by the National Institutes of Health that explores the amount of light it takes to impact sleep and circadian rhythms in young children. To do this, her study team goes into the homes of volunteer families and exposes children to varying intensities of light. They then collect saliva samples from the children to measure the change in melatonin levels and the timing of the biological clock. LeBourgeois hopes the results will demonstrate how little light it takes to affect sleep and circadian rhythms in kids and that this will inspire “science-based” screen-time guidelines for parents and device manufacturers. The CU Boulder paper tells us that the majority of research reveals that more digital media use is linked to delayed bedtimes, fewer hours of sleep, and poorer sleep quality for children whose eyes, brains, and sleep patterns are still forming. But, as parents, it can be hard to know where to draw the line. In the increasingly digital age we live in, banning all electronics from our homes seems pretty unrealistic – not to mention unappealing, because what about "This Is Us?" But shrugging our shoulders and hoping the issue doesn’t rob our kids of too much precious sleep doesn’t seem like the right answer either. Fortunately, LeBourgeois offers some helpful tips for parents about handling screen time at bedtime. She recommends that parents:
  • Limit children's media use in the hour before bedtime.
  • Turn off all electronic media devices, including yours, at bedtime, and charge them in a central location outside bedrooms.
  • Remove all electronic media from your child or teen's bedroom, including TVs, video games, computers, tablets, and cell phones.
That sounds like great advice that I’m going to keep in mind next time my son’s eyes light up and he says “Movie night!”



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