Children who spend time in front of the television or computer before bed fall asleep later than children who don’t, according to a new study from the University of Auckland in New Zealand.

Researchers studied the presleep habits of 2,017 children, ages 5 to 18, focusing on their activities during the 90-minute period before sleep. Habits were grouped into one of three categories: screen sedentary time, nonscreen sedentary time, and self-care. Behaviors were later analyzed against the child’s onset of sleep.

Results showed that children with delayed sleep had significantly greater engagement in screen time activities like television and computers. Researchers also found that children with an earlier sleep time spent significantly greater time in nonscreen activities and self-care.

On average, screen time activities accounted for one-third of the presleep period for all children, with TV watching as the most commonly reported activity.

Reducing screen time during the 90 minutes before sleep may promote earlier sleep and improve sleep duration in young people, the study concluded.

Researchers from The University of Auckland, University of South Australia, and Flinders University participated in the study, which was published in the journal Pediatrics.