Increased Sedentary Time in Children Linked to Higher Risk of Heart Attack, Stroke in Adulthood: Study

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Researchers in Finland have found that an increased sedentary lifestyle and inactivity as a child could lead to a higher chance of heart attacks and strokes later in life, even among individuals with normal weight and blood pressure.

The study, led by Dr. Andrew Agbaje of the University of Eastern Finland, Kuopio, Finland, was the first of its kind probing the cumulative effect of smartwatch-assessed sedentary time in young people and cardiac damage later in life.

It was conducted as part of the “Children of the 90s” study by the University of Bristol, in which over 14,000 children born between 1991 and 1992, as well as their families, were “intensively observed” for over 25 years in order to understand the environmental and genetic factors that affect health and development.

For the latest study, which was conducted among 766 children—of whom 55 percent were girls and 45 percent were boys—11-year-old children were given a smartwatch that tracked their activity for seven days.

The study participants were then given the smartwatch to wear for seven days again at ages 15 and 24.

Researchers then measured the weight of the heart’s left ventricle via echocardiography—a type of ultrasound scan that looks at the heart and its surrounding blood vessels—at 17 and 24 years of age and reported in grams relative to height.

They then analyzed the association between sedentary time between 11 and 24 years of age and heart measurements between 17 and 24 years after adjusting for factors that could influence the relationship, such as sex, blood pressure, body fat, smoking, physical activity, and socioeconomic status.

Study Findings

Researchers found that at 11 years of age, children were sedentary for an average of 362 minutes a day (roughly 6 hours), with this number rising to 474 minutes a day (8 hours) at the age of 15 and 531 minutes a day (nearly 9 hours) when the children reached the age of 24.

Overall, they found that sedentary time increased by an average of 169 minutes (nearly 3 hours) a day between childhood and young adulthood.

Each one-minute increase in sedentary time from 11 to 24 years of age was associated with a 0.004 g/m2.7 increase in left ventricular mass when the study participants were between 17 and 24 years of age, the researchers found.

“When multiplied by 169 minutes of additional inactivity this equates 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,” they wrote, noting that “a previous study in adults found that a similar increase in left ventricular mass (1 g/m2.7) over a seven-year period was associated with a two-fold increased risk of heart disease, stroke, and death.”

Multiple other studies have also found that an increase in left ventricular mass may lead to a higher risk of cardiovascular disease, coronary heart disease, heart failure, and stroke.

Parents Should Encourage Kids, Teens to ‘Move More’

According to the Centers for Disease Control and Prevention (CDC), someone has a heart attack every 40 seconds in the United States, while heart disease is the leading cause of death for men, women, and people of most racial and ethnic groups in the United States.

High blood pressure is a major risk factor for heart disease, while unhealthy blood cholesterol levels, diabetes, and obesity can also increase the risk of heart disease.

The CDC also notes that a lack of physical activity can lead to heart disease or increase risk factors associated with the disease.

“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,” said study author Dr. Agbaje.

“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,” she continued. “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.”

Researchers are set to present their preliminary findings at the European Society of Cardiology Congress later this month.