Weather 
At night, your teen should sleep like a baby.
They actually need more ZZZ’s than adults — up to 11 hours, compared to adults’ seven to nine hours— to support their rapidly developing brains and bodies.
That’s why losing sleep night after night is more than a bad habit. It has major consequences as teens grow into young adults.
Disrupted sleep in teens “can induce higher stress levels, more anxiety and even contribute to a depressed mood,” Dr. Daniel Bigman, a child and adolescent psychiatrist and sleep medicine physician at Northwell Health, told The Post.
Plus, “it can cause daytime sleepiness, lower motivation and even difficulty with impulse control or decision-making,” he added. “Every amount of sleep that’s lost is important because of these consequences.”
New research shows that a habit most teens are guilty of makes it harder for them to catch that quality slumber: Staying up on their phones.
Burning the midnight oil
Researchers from New York used a smartphone app and Fitbits to measure phone activity and sleep.
They found that teens who spent more time on their phones late at night fell asleep later and got less sleep.
For every 30 minutes on the phone after 10 p.m., teens fell asleep 26 minutes later, woke up 11 minutes later and got 12.9 minutes less sleep, compared to their usual sleep habits.
Separate research found that more than half of American teens are on their phones for an hour or more between 10 p.m. and 6 a.m. on school nights.
Whether they used their phones directly before sleep also mattered. Those who were on the phone in the five minutes before falling asleep had more disrupted sleep, especially during the first half hour.
To be exact, they found that each additional minute on their phone (within five minutes of falling asleep) made them wake up for about a minute after they went to sleep.
Teens were mostly on social media, including TikTok, YouTube and Snapchat, when they were supposed to be winding down for bed.
They were on social media after 8 p.m. for an average of 44 minutes per night, while other app categories accounted for less than six minutes a night. Social media was also used on more than half the nights measured.
Why it matters
Bigman, who didn’t participate in the new study, notes that it’s not just social media that can mess with sleep — it’s “any kind of activity.”
“Phones can be stimulating. And things like social media, videos, texting, notifications, lights, these are all signals to the brain that get transmitted through our senses, eyes and ears,” he said. “It tells our brain to stay alert when it really should be winding down.”
The light, especially, signals the brain it’s time to be awake, messing with the body’s natural sleep-wake cycle, he said.
This research improves on previous studies that analyzed self-reported data on smartphone use, which can be inaccurate. Researchers in this study used more objective measures through direct smartphone monitoring and Fitbits.
Bigman says this more reliable data provides additional evidence backing our hunch that being on our phones into the night is no good.
“Overall, we can say that from the study, we’re getting more specific advice or specific support towards reducing phone usage and reducing stimulation in the evening, especially before bedtime,” Bigman said.
His advice is for teens and folks of all ages: Keep a good nighttime routine and sleep hygiene — and your body will thank you.
“The idea should be that we want to limit phone use before sleep time, and we want to instead replace bedtime routines with other types of winding-down activities that may not be as stimulating,” he said. “Reading, music, relaxation exercises and stretching; other activities that we know promote a sleep environment.”
For your kids, encourage good habits rather than laying down the law. “My advice isn’t to try to punish teens for their day-to-day activities or their want to access their phones,” he said.
