Children staring at screens for too long - a looming risk for cardiovascular health.

A new study was published inJournal of the American Heart Association- Open-access, peer-reviewed scientific journals have sounded the alarm about the negative impact of excessive electronic device use on cardiovascular health.

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

The American Heart Association's 2023 annual report confirmed that cardiovascular and metabolic disorders are increasingly appearing at younger ages. In fact, only about 29% of American children and adolescents aged 2 to 19 have adequate cardiovascular and metabolic health records, based on national data collected between 2013 and 2018.

The latest analysis, based on more than 1,000 participants from two large-scale studies in Denmark, further strengthens this link. The research team at the Copenhagen Centre for Prospective Study of Childhood Asthma (COPSAC), University of Copenhagen, tracked data from a group of 10-year-olds (2010) and an 18-year-old group (2000). The results showed that the more time spent in front of screens for entertainment, the greater the risk of cardiovascular adverse events.

Dr. David Horner, the study's lead author, emphasized: “Limiting screen time in children and adolescents is key to long-term cardiovascular health protection. This evidence shows that unhealthy habits can be formed very early, and building a balanced daily lifestyle is extremely important.”

What are the effects of screen time on children's cardiovascular health?

To accurately assess the link between electronic device use and cardiovascular health, the research team developed a composite scoring system that reflects cardiovascular risk.

This score is calculated based on five key factors of metabolic syndrome, including waist circumference, blood pressure, levels of "good" cholesterol (HDL), triglycerides, and blood glucose, and is adjusted for sex and age. On this scale, 0 is considered the mean, while 1 represents a risk one standard deviation higher than the mean of the study group.

Analysis results show that for 10-year-olds, each additional hour spent in front of a screen increases the risk score by 0.08 standard deviations; for 18-year-olds, this figure is 0.13. Dr. David Horner, the lead author, explains: “A child who watches an extra three hours a day may face a risk that is between one-quarter and nearly one-half standard deviations higher than their peers. This may seem like a small change per hour, but when added 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 a crucial role. Sleeping less or going to bed late increases the negative impact of screen time on cardiovascular health.

Approximately 12% of the link between screen time and metabolic risk is attributed to shorter sleep duration. Horner emphasizes: “Sleep deprivation not only exacerbates the effects of electronic device use but may also be a key mechanism linking this habit to early metabolic changes.”

Biological markers of screen usage habits in blood analysis

Beyond the link between screen time and cardiovascular health, scientists have discovered a unique biological signal in the blood, dubbed the "screen time marker." Analysis using machine learning algorithms revealed significant changes in blood metabolism, reflecting the potential biological impact of excessive screen time.

Dr. David Horner stated: “We found a range of changes in blood metabolic profiles, a characteristic marker directly related to screen time. Using this data, we assessed whether this factor predicts 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 become indicators of long-term cardiovascular problems.”

According to the research team, identifying screen time habits should be included in pediatric health checkups, just as doctors typically discuss diet or exercise levels. Metabolic markers in the blood could become an objective tool for early prediction of lifestyle-related health risks.

Dr. Amanda Marma Perak, chair of the Young Hearts Committee on Cardiovascular Disease Prevention at the American Heart Association, emphasizes that sleep can be a practical starting point for change. “If cutting screen time is too difficult, try adjusting by shifting your screen time to earlier in the day, and prioritize going to bed early and getting enough sleep,” she recommends.

The role of parents and adults

Experts emphasize that adults themselves need to set a good example in their use of electronic devices. "We all use screens every day, so it's important to guide children and teenagers to use them in a healthy way, appropriate for their developmental stage," one expert stated.

As parents, setting a good example is essential, knowing when to put away devices, how to use them, and avoiding multitasking while using screens. As children get older, parents can clearly explain why the whole family should limit screen time during dinner or other quality family time.

Furthermore, it's crucial to teach children how to entertain themselves and overcome boredom without relying on screens. "Boredom can foster intelligence and creativity. When your child complains of boredom, it's actually an opportunity to teach them how to deal with unpleasant emotions in a healthy way without device dependence," the expert emphasized.

However, the research team noted that the current findings are only observational, reflecting an association rather than proving cause and effect. Additionally, the screen time reported by parents through surveys may not accurately reflect reality.

According to Dr. Horner, future research could focus on limiting screen time in the hours leading up to sleep. Blue light from screens can disrupt circadian rhythms and delay sleep, thereby contributing to increased cardiovascular and metabolic risks.