A newly published study has raised alarms among parents, teachers, and health professionals by revealing a clear link between excessive screen time and increased heart health risks in children and adolescents. The research, released in early August 2025 in the Journal of the American Heart Association, adds crucial evidence to ongoing debates about digital device use among youth. As the ubiquity of smartphones, tablets, computers and game consoles continues to reshape how children and teens spend their days—including in urban and rural households across Thailand—doctors caution this is more than a question of eye strain or distraction: it’s about the lifelong health of a new generation.
The study analyzed data from over 1,000 participants aged 10 and 18 in Denmark, tracking time spent on screens—including televisions, mobile phones, computers, and gaming devices. Researchers assigned each participant a cardiometabolic risk score, estimating their relative risk of developing conditions like high blood pressure, elevated cholesterol, and insulin resistance, all of which are associated with later heart disease and diabetes. What they discovered was striking: every additional hour of daily screen time increased cardiometabolic risk by roughly 0.08 standard deviations for 10-year-olds and 0.13 standard deviations for 18-year-olds, compared to the group average. These increments might sound small, but they add up fast: many adolescents spent as much as six hours a day on screens, while 10-year-olds averaged about three hours.
Lead researcher Associate Professor at the University of Copenhagen emphasized, “It’s a small change per hour, but when screen time accumulates to three, five, or even six hours a day, as we saw in many adolescents, that adds up.” The study further found that sleep habits played a crucial role. Both shorter sleep duration and later bedtimes—patterns often observed in children who use screens before bed—amplified the negative relationship between screen time and heart health. Researchers speculate that screens may pose their greatest threat to long-term health not just by keeping children sedentary, but by “stealing” precious hours from restorative sleep.
Why should Thai parents and educators be concerned? Screen time has soared in Thailand during the post-pandemic period, especially among primary and secondary school students. Data from recent years show that Thai youth spend between 3 and 7 hours a day on digital devices, often for a mix of educational and entertainment purposes (CDC: Daily Screen Time Among Teenagers). This aligns with policy observations in Thailand; education specialists and pediatricians in Thai hospitals and universities have already expressed concern over screen-induced sedentary behaviors and their downstream effects on public health (health.choc.org). Physical inactivity linked to excessive screen use has been associated with the rise of childhood obesity in the country—a risk factor that compounds cardiovascular disease later in life.
Importantly, this new study is observational—it cannot conclusively prove that screen time directly causes heart disease. Other factors, such as diet, genetics, or family lifestyle, may also contribute. However, its findings build upon a growing international consensus, reflected in guidelines from the World Health Organization and supported by pediatric associations across Asia, cautioning against unmonitored daily screen use.
Cardiology experts from the Danish research team suggest moderation as the best course. “Limiting discretionary screen time in childhood and adolescence may protect long-term heart and metabolic health," the lead author remarked. “Our study provides evidence that this connection starts early and highlights the importance of having balanced daily routines.” Practical recommendations include setting daily screen time limits, encouraging children to follow regular sleep schedules, and prioritizing outdoor activities or family exercise wherever possible. For Thai families, this could mean establishing “offline hours” in the home or schools, encouraging community sports, or exploring local cultural and recreational spaces.
This is not the first time researchers have linked screen time to adverse health effects among the young. Studies published in the last two years have documented increased rates of obesity, poor sleep quality, and even mental health difficulties such as anxiety and depressive symptoms in youth who exceed two hours of non-academic screen use daily (newsroom.heart.org). The U.S. Surgeon General’s advice to parents—create “tech-free zones” and times at home—has already influenced some Thai child development policy proposals.
The matter is also intertwined with broader cultural and economic shifts. In many Thai households, devices serve essential educational roles, especially in remote learning or low-resource settings. Likewise, with urbanization and traffic, safe outdoor play opportunities can be limited, prompting parents to allow more screen use indoors for practicality and perceived safety. Yet, as physicians at Chulalongkorn University Hospital and public health leaders at the Ministry of Public Health have cautioned, well-meaning reliance on screens can inadvertently set up children for a lifetime of habits that undermine their heart health.
The research community continues to explore not only the quantitative limits of safe screen use but also its qualitative aspects—which forms of digital engagement are most detrimental, and for whom? Future studies are expected to further disentangle the effects of interactive screen use (e.g., gaming, social media) versus passive (e.g., watching TV), the impact of blue light exposure before bedtime, and associations with mental health and learning outcomes. Meanwhile, some Thai educators are piloting blended learning models, combining limited screen-based education with hands-on STEAM activities and supervised play.
Looking forward, if prevention efforts are strengthened now, the incidence of cardiovascular disease and diabetes among Thai youth can be slowed, sparing families and national healthcare systems enormous future costs. Health professionals encourage parents and caregivers to monitor their children’s screen time, set regular technology “curfews,” and serve as role models for non-digital leisure activities. Community groups should work with local authorities to make parks and cultural centers safer and more accessible, incentivizing healthier alternatives to screen-based recreation.
For parents and teachers seeking practical steps: aim to limit your child’s recreational screen use to two hours or less each day. Establish predictable, device-free bedtimes. Encourage frequent activity breaks during homework or online learning. Model technology etiquette by practicing what you preach—and remember, it’s not about total prohibition, but about fostering a balanced, heart-healthy daily routine grounded in Thai family and community values.
For further reading, see the original research (CBS News), review coverage on newsroom.heart.org, and consult Thai public health resources for locally tailored recommendations.