Bedtime Smartphone Use and Adolescent Sleep Study Context

Researchers wanted to investigate the impact of pre-bedtime smartphone use on the sleep duration of adolescents.

They conducted a meta-analysis on studies published between 2005 and 2022 involving adolescents aged 12–19 years old, looking at how different patterns of interactive screen exposure in the hour before sleep affected their total nightly sleep.

Screen exposure included checking social media, messaging, and mobile gaming on smartphones. The researchers included studies from all countries and languages, but excluded adult studies, daytime-only screen usage, and clinical populations with diagnosed sleep disorders.

They compared findings from studies focused on smartphone use to those focused on non-screen bedtime activities, such as reading physical books or listening to the radio. Their final analysis included 14 studies on bedtime smartphone use and 6 studies on physical book reading.

The researchers reviewed two main methodological approaches in the gathered literature:

• Experimental evidence: Laboratory-based sleep studies where participants were randomly assigned to use a smartphone or read a physical book for 45 minutes before bedtime, with sleep duration measured via polysomnography.
• Non-experimental evidence: Survey-based longitudinal studies utilizing daily self-reported sleep diaries and tracking apps to assess typical weekly routine and sleep duration.

For the experimental evidence, the meta-analysis found that smartphone use immediately before bed reduced sleep duration by an average of 42 minutes compared to non-screen activities. In the non-experimental evidence, there was a significant negative correlation between the frequency of nighttime screen checks and cumulative weekly sleep hours.

The study concluded that bedtime smartphone use significantly reduces overall sleep duration in adolescents.