Children glued to screens for too long - cardiovascular risk lurking

A new study published inJournal of the American Heart Association- An open, peer-reviewed scientific journal has sounded the alarm about the negative impact of electronic device abuse on cardiovascular health.

Scientists point out that spending too much time in front of the screen watching movies, playing games, using phones or computers not only affects lifestyle but also increases the risk of cardiovascular and metabolic problems, including high blood pressure, increased cholesterol and insulin resistance.

The American Heart Association’s 2023 Annual Report states that cardiovascular and metabolic disorders are occurring at increasingly younger ages. In fact, only about 29% of American children and adolescents aged 2 to 19 have a standard cardiovascular and metabolic health profile, based on national data collected between 2013 and 2018.

The latest analysis, based on more than 1,000 participants from two large studies in Denmark, further strengthens this link. Researchers from the Copenhagen Prospective Study of Asthma in Childhood (COPSAC) at the University of Copenhagen looked at data from a group of 10-year-olds (2010) and a group of 18-year-olds (2000). The results showed that the more time spent in front of a screen for entertainment, the higher the risk of adverse cardiovascular factors.

“Limiting screen time in children and adolescents is key to protecting long-term cardiovascular health,” said lead author Dr David Horner. “This evidence shows that unhealthy habits can form early in life, and that establishing a balanced daily routine is crucial.”

What is the impact of screen use on children's cardiovascular health?

To accurately assess the link between electronic device use and cardiovascular health, the research team constructed a composite score reflecting cardiovascular risk.

The score is based on five key indicators of metabolic syndrome, including waist circumference, blood pressure, “good” (HDL) cholesterol, triglycerides, and blood sugar, and is adjusted for sex and age. On this scale, 0 is considered average, while 1 represents a risk greater than one standard deviation above the study group’s mean.

The analysis found that for 10-year-olds, each additional hour spent in front of a screen increased their risk score by 0.08 standard deviations; for 18-year-olds, it was 0.13. “A child who watches an additional three hours a day may face a risk that is between a quarter and nearly half a standard deviation higher than their peers,” explains lead author Dr. David Horner. “This may seem like a small change per hour, but when it adds up to three, five, or even six hours a day, the impact becomes significant and has long-term consequences.”

In addition to screen time, the study also found that sleep plays an important role. Sleeping less or going to bed later increases the negative impact of screen time on cardiovascular health.

An estimated 12% of the association between screen time and metabolic risk was explained by shorter sleep. “Not only does sleep deprivation exacerbate the effects of electronic device use, it may also be a key mechanism linking this habit to early metabolic changes,” Horner notes.

Biomarkers of screen use in blood analysis

Beyond the link between screen time and cardiovascular health, scientists have also discovered a unique biomarker in the blood, dubbed the “screen time signature.” Machine learning analysis has revealed significant changes in blood metabolism, reflecting the potential biological effects of spending too much time in front of a screen.

“We found a range of changes in blood metabolic profiles, a signature marker directly linked to screen time,” said Dr David Horner. “Using this data, we assessed whether this factor predicted cardiovascular risk in adulthood, and the results showed a clear trend in children, as well as a significant association in adolescents. This means that early metabolic changes may be a marker for long-term cardiovascular problems.”

Screen time should be included in well-child visits, the researchers say, just as doctors discuss diet and exercise levels. Metabolic markers in the blood could become an objective tool to predict lifestyle-related health risks early on.

Dr. Amanda Marma Perak, chair of the American Heart Association’s Young Hearts Prevention Committee, emphasized that sleep can be a practical starting point for change. “If cutting back on screen time is too difficult, try adjusting by shifting screen time to earlier in the day and prioritizing going to bed earlier and getting enough sleep,” she recommended.

The role of parents and adults

Experts stress that adults also need to be role models when it comes to using electronic devices. “We all use screens every day, so it is important to guide children and adolescents in healthy, developmentally appropriate use,” one expert said.

As parents, it’s important to set an example, knowing when to put away devices, how to use them, and avoiding multitasking. As children get older, parents can clearly explain why the family will limit screen time during dinner or other family time.

It’s also important to let kids learn how to entertain themselves and overcome boredom without screens. “Boredom can foster intelligence and creativity. When your child complains that they’re bored, it’s actually an opportunity to teach them how to deal with unpleasant emotions in a healthy way without relying on devices,” the expert emphasized.

However, the researchers note that the current findings are observational and reflect an association, not a cause-and-effect relationship. Additionally, children’s screen time was reported by parents through surveys, which may not accurately reflect reality.

Future research could focus on limiting screen use in the hours before bed, Dr. Horner said. Blue light from screens can disrupt circadian rhythms and delay sleep, which can contribute to increased cardiovascular and metabolic risks.