Too Much Screen Time May Be Messing With Kids’ Hearts, New Study Warns

We all know screens aren’t exactly doing kids’ attention spans any favors — but new research says the impact might go way deeper than we thought. A study just published in the Journal of the American Heart Association reveals that more screen time in kids and teens is linked to real, measurable risks to heart and metabolic health.

That’s right: TikTok binges, YouTube marathons, gaming sessions — it’s not just about sore eyes and missed homework anymore. According to researchers, all those hours glued to a screen could be setting kids up for long-term issues like high blood pressure, elevated cholesterol, insulin resistance, and even belly fat — all signs of developing cardiometabolic disease.

Scientists in Denmark pulled data from over 1,000 kids (ages 10 and 18) and tracked their screen time, sleep patterns, and health markers like cholesterol, blood sugar, and blood pressure. What they found wasn’t great.

For every extra hour spent on screens, a kid’s risk for heart and metabolic problems ticked up — by 0.08 standard deviations for 10-year-olds, and 0.13 for teens. That may sound small, but when screen time hits 3, 5, or even 6 hours a day (as it often does), those risks start stacking up fast.

“It’s a small change per hour, but when screen time accumulates, that adds up,” said lead researcher David Horner from the University of Copenhagen. “Across an entire generation, it could mean a real shift in long-term heart health.”

And here’s where it gets even trickier: Less sleep and later bedtimes made everything worse. The researchers believe screen time isn’t just harmful on its own — it’s also stealing sleep from kids, and that might be a big part of what’s putting their health at risk.

In fact, they found that about 12% of the heart risk linked to screen time could be blamed directly on shorter sleep.

Using artificial intelligence, researchers also discovered something wild: kids’ blood markers could actually predict how much time they were spending on screens. They called it a “screen-time fingerprint” — a biological signature that hinted at the hours spent scrolling, watching, or gaming.

Even more concerning? Teens showed early signs of the kind of cardiovascular risk that typically doesn’t show up until adulthood.

Doctors are now saying it’s time to talk about screen time during checkups — not just how it affects focus or mood, but how it might be shaping long-term health.

Dr. Amanda Marma Perak, a pediatric heart expert with the American Heart Association, says a good first step is adjusting the timing of screen use.

“If cutting back feels hard, start by moving screen time earlier in the day,” Perak said. “Then focus on getting kids to bed earlier — and for longer.”

She also urges parents to model healthy habits themselves. Don’t just tell kids to put their phones down — show them by doing it at dinner, during conversations, or before bed.

“It’s also okay if kids are bored sometimes,” Perak added. “Boredom breeds creativity. Not every quiet moment has to be filled with a screen.”

Before you panic, keep in mind: this was an observational study, which means it found a connection — not direct proof that screen time causes health problems. Plus, the screen-time data was self-reported, so it’s possible people under- or overestimated.

Still, this adds to growing evidence that the digital lives of today’s kids could have real consequences down the line.

If your kid’s screen time is climbing and their bedtime’s drifting later, it might be time to hit pause. Heart health isn’t just something to worry about at 50 — it might start way earlier than we thought. And yes, that next Netflix episode can wait.

With input from CBS News, ABC News, and US News & World Report.