Study links pre-bedtime smartphone use to longer teen late nights

A new study to be presented at the SLEEP 2026 annual meeting found that on evenings when adolescents used their smartphone before bedtime more than their own usual, they used their smartphone for longer later that same night, compared with nights when they used their phones less before bedtime.

Results from within-person analyses show that on nights when adolescents used their smartphones for an additional 20 minutes in the hour before bedtime (10:23 PM–11:23 PM on school nights and 11:25 PM–12:25 AM on non-school nights), they had 8-9 more minutes of late-night (midnight–5:00 AM on school nights and 1:00 AM–6:00 AM on non-school nights) use later that same night. On average, adolescents with greater pre-bedtime smartphone use had greater late-night use; adolescents with an average of 20 minutes of pre-bedtime smartphone use had 37-41 minutes of average late-night use. Moreover, teens used their smartphones for an average of 46 minutes each late night.

"On evenings when adolescents used their smartphone more before bed, they used it for a longer time later that night, potentially leading to later bedtimes and greater sleep disruption," said lead author Gina Marie Mathew, who has a doctorate in biobehavioral health and is a senior post-doctoral associate in the program in public health, department of family, population, and preventive medicine, Renaissance School of Medicine at Stony Brook University in Stony Brook, New York. "Limiting smartphone use before bed may help reduce nighttime phone use and thereby improve sleep among teens."

The American Academy of Sleep Medicine recommends that teenagers 13-18 years of age sleep 8-10 hours on a regular basis to promote optimal health. The AASM also suggests turning off electronic devices 30-60 minutes before bed.

The study recruited 230 adolescents from across the United States who owned or were the primary user of a personal smartphone (46% female, 47% male, 7% other). Participants completed a survey querying sociodemographic characteristics and sleep timing, and then they installed RealityMeter, an app that passively and objectively measured smartphone use over an average of approximately 17 days.

Mathew noted that the objective, passive measurement of smartphone use in this study provides a more accurate picture of adolescent nighttime media habits than self-report alone.

"Using passively measured, objective smartphone data allowed us to examine these associations at the within-person, nightly level, providing a granular look at how pre-bedtime phone use predicts additional late-night use in adolescents' daily lives," Mathew said.

This study was supported by the Della Pietra Family Foundation. The research abstract was published recently in an online supplement of the journal Sleep and will be presented June 15 during SLEEP 2026 in Baltimore. SLEEP is the annual meeting of the Associated Professional Sleep Societies, a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.

Source:

American Academy of Sleep Medicine

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