In a recent blog we talked about the value of limiting screen time for young users in favor of more traditional forms of social interaction. Add to that new research showing the negative impact of electronic devices on sleep patterns, and you have compelling reasons to carefully monitor your child’s use of smartphones, tablets, and other digital products, especially at night.

The latest research, published in the journal Pediatrics, and reported in Bloomberg Businessweek, found that children who slept in the same room with small screens got less sleep than those who didn’t. The two age groups studied were 9-year-olds and 12-year-olds. Researchers speculated that message alerts interrupting the body’s natural circadian rhythms, were responsible for up 21 fewer minutes of shut-eye per night.

According to the Bloomberg article, this study contributes to the growing body of research suggesting that exposure to electronic devices at night is potentially harmful to your child’s health:

While the Pediatrics study didn’t conclude that phones cause sleep deprivation, its lead author, Jennifer Falbe, said the case for clamping down on kids’ screen time is gaining strength.

Recent findings “caution against unrestricted access to media in children’s bedrooms,” Falbe, a researcher at the University of California at Berkeley, said in a phone interview. “The risks associated with shorter sleep duration and poorer sleep quality would include reduced academic performance, behavioral problems, possibly an increased risk for weight gain and possibly negative impacts on immunity.”