DARIEN, IL – 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.
