UNIVERSITY PARK, Pa. – It may be tempting to let your kids stay up late playing games on their smartphones, but using digital devices before bed may contribute to sleep and nutrition problems in children, according to Penn State College of Medicine .
After surveying parents about their kids' technology and sleep habits, they found that they used TV and used their cell phones before bed – higher body mass indexes (BMI).
Caitlyn Fuller, medical student, said the results – published in the journal Global Pediatric Health – may suggest a vicious cycle of technology used, poor sleep and rising BMIs.  "We saw technology before bed being associated with less sleep and higher BMIs," Fuller said. "We also saw this technology use being associated with more fatigue in the morning, which is circling back, is another risk factor for higher BMIs. So we're seeing a loop pattern forming. "
Previous research you've found associations between more technology use and less sleep, more inattention, and higher BMIs in adolescents. But even though research shows that 40 percent of children have cell phones by fifth grade, the researchers said that because of the effects of technology on a younger population.
, she was interested in learning more about the connection between screen time right before bed and how well those children slept, as well as how it affected other aspects of their health.
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After analyzing the data, the researchers found several adverse effects associated with using different technologies right before bed .
"We found an association between higher BMIs and an increase in technology use, and also that children who reported more technology at bedtime were associated with less sleep at night," Fuller said. "These children were also more likely to be tired in the morning, which is also a risk factor for higher BMIs."
Children who reported watching TV or playing video games before bed got an average of 30 minutes less sleep than those who did not, while kids who used their phone or a computer before bed averaged an hour less of sleep than those who did not.
There was also an association between using all four types of technology before bed and increased cell phone use at night , as if waking up to somebody, with watching TV resulting in the highest odds.
Fuller said the results supported new from the American Academy of Pediatrics (AAP) about screen time for children. The AAP recommends that parents create boundaries around technology use, such as requiring their children to put away their devices during meal times and keeping phones out of bedrooms at night.
Dr. Marsha Novick, associate professor of pediatrics and family and community medicine, said that while more research is needed to determine whether multiple devices at bedtime results in worse than just one device, the study can help pediatricians talk to parents about the use of technology.
"Although there are many benefits to using technology, pediatricians may want to counsel parents about limiting technology for their kids, particularly at bedtime, to promote healthy childhood development and mental health," Novick said.
Dr. Steven Hicks, assistant professor of pediatrics, and Eric Lehman, biostatistician, also participated in this study.
This research was supported by the Bedrick Family Medical Student Research Program and the Penn State Clinical and Translational Research Institute.