That was true even when the adult’s blood pressure and weight were healthy, according to researchers.
“All those hours of screen time in young people add up to a heavier heart, which we know from studies in adults raises the likelihood of heart attack and stroke,” said study author Dr. Andrew Agbaje, of the University of Eastern Finland in Kuopio.
“Children and teenagers need to move more to protect their long-term health,” he explained in a news release from the European Society of Cardiology.
This was the first study to investigate the cumulative effect of smartwatch-assessed sedentary time in young people and cardiac damage later in life, the study authors noted.
Kids who were part of the Children of the 90s study wore a smartwatch activity tracker for seven days at age 11, and then repeated this at age 15 and age 24.
The researchers assessed the weight of the heart’s left ventricle by echocardiography, a type of ultrasound scan, at 17 and 24 years of age. Results were reported in grams relative to height.
The researchers then analyzed the association between sedentary time between age 11 and 24 and heart measurements between age 17 and 24.
The study included 766 children, of whom 55% were girls and 45% were boys. At age 11, children were sedentary for an average of 362 minutes a day, rising to 474 minutes a day in adolescence and 531 minutes a day in young adulthood.
That sedentary time was an increase of an average of 2.8 hours a day between childhood and young adulthood.
The team found that each one-minute increase in sedentary time from age 11 to 24 was associated with a 0.00 g/m2.7 increase in left ventricular mass between ages 17 and 24. In other words, the heart got heavier.
They also found that when multiplied by 169 minutes of additional inactivity this was equal to a 0.7 g/m2.7 daily rise — the equivalent of a 3 gram increase in left ventricular mass between echocardiography measurements at the average height gain.
In adults, a previous study found that a similar increase in left ventricular mass over a seven-year period was associated with a twofold increased risk of heart disease, stroke and death.
“Children were sedentary for more than six hours a day and this increased by nearly three hours a day by the time they reached young adulthood. Our study indicates that the accumulation of inactive time is related to heart damage regardless of body weight and blood pressure. Parents should encourage children and teenagers to move more by taking them out for a walk and limiting time spent on social media and video games,” Agbaje said.
“As Martin Luther King Jr. once said, ‘If you can’t fly, run. If you can’t run, walk. If you can’t walk, crawl. But by all means keep moving,’” he added.
The research was scheduled for presentation Aug. 25 to 28 at the European Society of Cardiology meeting, in Amsterdam, the Netherlands. Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.
The U.S. Centers for Disease Control and Prevention has more on physical activity and children.
SOURCE: European Society of Cardiology Congress 2023, news release, Aug. 23, 2023
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