Do Screens Before Bed Really Impact Teen Sleep?

Bradley Brosnan, PhD

Credit: LinkedIn

Screen time in the two hours before bed did not significantly impact most sleep health measures among children aged 11 to 14. However, screen use once in bed, particularly interactive activities like gaming and multitasking, was associated with shorter sleep durations and delayed sleep onset. Investigators say the findings suggest that not all pre-bed screen time impairs sleep, indicating that current sleep hygiene guidelines may need adjustment.

“Our findings challenge the conventional belief that screen use before bed is always detrimental to sleep,” wrote a team of researchers led by Bradley Brosnan, PhD, associated with the Department of Medicine at University of Otago, Dunedin, New Zealand.

The American Academy of Pediatrics and international government health organizations recommend adolescents stop using screens one to two hours before bed to help encourage good sleep. However, most youths extend their screen activity into nighttime hours. These guidelines largely base their evidence on studies with inherent limitations, such as evaluating screen use over the whole day or using self- or parent-reported data on screen use instead of assessing the specific device or activity types that may impact sleep differently.

Despite previous research using questionnaires indicating screen time before bed is associated with poor sleep, objective measures are necessary to advance this field. Therefore, investigators conducted a repeated-measures cohort study between March and December 2021 in New Zealand. Eligible patients were healthy kids aged 11 to 14.9 years. Screen time was objectively measured using wearable or stationary video cameras from 2 hours before bedtime until first attempted sleep—defined as the first time participants shut their eyes—over a 4-night period. Sleep duration and quality were determined using wrist-worn accelerometers.

Among the 79 subjects recruited into the study, 59.5% were male and the mean age was 12.9 years. All but 1 participant had screen time before bed.

Screen time in the two hours prior to bedtime was not linked with most measures of sleep health, with no difference in total sleep time for every 10 minutes more of total screen time.

Although all types of screen time were associated with delays in the onset of sleep, interactive screen use was particularly linked to delays of 4 to 16 minutes for each additional 10 minutes of interactive screen use. Each 10-minute increment of additional screen time in bed correlated with a shorter total sleep time. Interactive screen use was shown to decrease sleep time by 9 minutes for every 10 minutes and passive screen use shortened total sleep time by 4 minutes. In terms of interactive screen time, gaming and multitasking reduced total sleep time by 17 minutes and 35 minutes, respectively.

Overall, the total screen time was not associated with either bedtime or how much a participant woke up after first going to sleep on nights with screen use compared to without screen use. Although screen time was linked to extended shut-eye latency (time spent in bed before trying to go to sleep), it did not affect sleep latency (how long it took to go to sleep once they started trying).

The study was the first to objectively quantify passive, interactive and multitasking screen activities as well as their timing across devices to determine any associations with sleep outcomes in this patient population. However, limitations included the labor-intensive process of manually coding the video data, which took approximately 1,080 hours. Additionally, there is a possibility that participants could have changed their behavior because they were aware that they were being observed. However, subjects told investigators that they quickly forgot about the cameras, indicating minimal behavioral modification.

“The findings suggest that sleep hygiene guidelines restricting the use of screen media prior to sleep require clarification,” investigators concluded.