We all know that bright screen exposure during night time is harmful to adults and adolescents, what more with children? A new study from the University of Colorado Boulder has begun to explore how bright screens disrupt preschoolers' sleep. And this can lead to sleep problems later on.
Smart devices have, by now, become a part of our daily lives. In 2006, a survey showed that nearly all adolescents have at least one electronic device in their bedroom.
The quality of sleep in preschoolers
The study, published in the journal Physiological Reports, looked into the hormonal effects that bright screen exposure could have on the quality of sleep among preschoolers.
They focused on melatonin, the hormone responsible for the body’s naturally occuring circadian rhythm, inducing sleep and regulating the sleep-wake cycle.
Melatonin is also a component in other physical processes, like regulating temperature, blood pressure, and metabolizing glucose. Both adults and children need it to maintain a healthy sleep cycle.
"Although the effects of light are well studied in adults, virtually nothing is known about how evening light exposure affects the physiology, health, and development of preschool-aged children," says lead author Dr. Lameese Akacem.
Akacem is a CU Boulder instructor and researcher in the Sleep and Development Lab. He adds, "In this study, we found that these kids were extremely sensitive to light."
Due to the anatomical and structural differences between the eyes of children and adults, they are naturally more sensitive to light compared to other age groups.
How smart devices disrupt preschoolers' sleep
The researchers tested their hypothesis in ten children, ages three to five. They asked the children to follow a regular sleep schedule for five days to establish a pattern for their body clocks to settle into. They checked their saliva several times a day to measure the kids’ baseline levels of melatonin.
On the sixth day, the researchers transformed the children’s homes into low light “caves.” They covered the windows with black plastic and changed their light fixtures into low-wattage light bulbs.
For one hour the next evening, the children played with magnetic tiles on top of a light-up table meant to replicate the light of smartphones or tablets. The light emitted 1,000 lux (a unit of measurement for luminosity) of light. Then the researchers collected data again afterwards.
When the researchers compared the results with the night before, they found that the children’s melatonin levels had drastically dropped. Their melatonin levels were 88% lower after exposure to bright light. And these levels remained low for almost an hour after the lights were turned off. Most of the children’s melatonin levels didn’t even increase to 50% of the previous day’s levels.
“We found that the bright light exposure suppressed melatonin by almost 90 percent, and the effects persisted even after the kids returned to dim light,” says Dr. Akacem.
More studies on how smart devices disrupt preschoolers' sleep
However, the study needs to be replicated as the sample size is severely limited. The light used is also brighter than what is typically emitted from digital screens.
The researchers did note however that in a previous study, an hour of light (10 times more powerful than the current study’s light) lowered adults’ melatonin by 39%.
It’s important for people to remember that the amount of melatonin produced in the brain is influenced by exposure to light. Dr. Akacem explains that “the lens is a lot clearer” in the eyes of preschool children. "The pupils are larger, which allows more light to hit the retina and a stronger signal to the clock," she said.
Don't let these disrupt preschoolers' sleep
Just last year, a survey in the US revealed that the use of electronics by young children ballooned to three times its number from 2013. This is due to the rise of easily accessible, handheld devices such as tablets and smartphones.
"One important takeaway is that parents should avoid having children exposed to very bright light before bedtime," Dr. Akacem said.
It has become clear that limiting screen time before bedtime can help to avoid sleep deprivation. One solution is removing electronic devices from the bedroom — whether a parent’s or a child’s — thus providing a good sleeping environment and good sleep practices.
How not to disrupt preschoolers' sleep
Some public guidelines have recommended limiting the screen time exposure of children under 13 years to two hours a day. Meanwhile children below five must get less than an hour of it. However, worldwide standard screen time for children has yet to be precisely established.
As with everything, moderation is key. Parents must be mindful and have a more balanced approach when it comes to the use of smart devices. We can still have the benefits of such technologies without endangering the health of our children.
Source: Medical Daily, Fatherly, IFL Science
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Republished with permission from: theAsianParent Singapore