A new study shows that many teenagers are losing important sleep because of late-night phone use. Researchers found that teens spend more than 50 minutes on their smartphones between 10 p.m. and 6 a.m. on school nights.
The study, published in JAMA Pediatrics in May 2026, looked at 657 adolescents across the United States. It used a special app to track real phone use instead of asking teens to remember. This gave more honest results.
Surprisingly, more than half (52.1%) of the teens used their phones between midnight and 4 a.m. — a time when they should be sleeping deeply. Most of this time was spent on social media apps like YouTube, Instagram, and TikTok. Some also watched streaming videos or played games such as Roblox and Clash Royale.
Lead researcher Dr. Jason Nagata from the University of California, San Francisco (UCSF), said he was surprised by how many teens wake up in the middle of the night to use their phones. “That’s a really critical window when kids should be asleep,” he noted.
Experts explain that bright screens and exciting content overstimulate the brain. This makes it harder to fall asleep and stay asleep. Blue light from phones can also reduce melatonin, the hormone that helps us sleep.
Lack of sleep affects teens badly. It can lower school grades, increase mood problems, weaken the immune system, and raise risks for obesity and mental health issues. Teens need 8 to 10 hours of sleep each night for healthy growth.
Parents and schools should encourage better habits, such as keeping phones out of bedrooms at night. The study highlights the need for more awareness about digital habits and teen sleep health.
