Looking at bright screens before going to bed can affect the sleep patterns of young teenagers, reveals a new study.
The study found that that the sleep biology of boys and girls aged 9 to 15 who were in the earlier stages of puberty were especially sensitive to light at night compared to older teens. In lab experiments, an hour of nighttime light exposure suppressed their production of the sleep-timing hormone melatonin, significantly more than the same light exposure did for teens aged 11 to 16 who were farther into puberty.
The brighter the light in the experiments, the more melatonin was suppressed. Among 38 children in early to middle puberty, an hour of 15 lux of light suppressed melatonin by 9.2 percent, 150 lux reduced it by 26 percent, and 500 lux reduced it by 36.9 percent.
Senior author Mary Carskadon of the Brown University said that small amounts of light at night, such as light from screens, could be enough to affect sleep patterns. Carkadon added that students who had tablets or TVs or computers were pushing their circadian clocks to a later timing, which made it harder to go to sleep and wake up early the next morning for school.
Carskadon concluded that children and their parents should limit the use of bright screens at bedtime, even though it had become pervasive. The study is published in the Journal of Clinical Endocrinology and Metabolism.