Pathological increases in the heart’s left ventricle typically arise from diseases or unhealthy behaviors, such as increased sedentary time, and can negatively affect heart function. These changes usually manifest in adulthood and are robust predictors of cardiovascular disease-related death. Physiological increases in the left ventricle, on the other hand, are beneficial adaptations that occur in response to healthy activities, such as moderate-to-vigorous physical activity. These changes promote a stronger and more efficient heart muscle without the adverse effects associated with pathological enlargement. A recent study found that sedentary behavior induces pathological increases in left ventricular mass in children.
Researchers monitored the health and activity levels of more than 1,600 children enrolled in the Avon Longitudinal Study of Parents and Children from age 11 to 24 years. The children wore accelerometers during waking hours on two or more weekdays and one weekend day at least once during the 13-year study. They underwent echocardiography at the ages of 17 and 24 years.
At age 11, the children averaged six hours of sedentary time daily, increasing to nine hours by age 24. Cumulative sedentary time contributed to 40 percent of the pathological increase in left ventricular mass during adolescence, regardless of the children’s sex, body weight, or blood pressure. Children who were more sedentary had higher body fat, inflammation, blood pressure, lipid levels, and left ventricular mass, increasing their future cardiovascular risks.
Conversely, cumulative light physical activity (about three hours daily) reduced pathological increases in left ventricular mass by 49 percent. Each minute of moderate-to-vigorous physical activity induced physiological increases in left ventricular mass of 5 percent.
These findings suggest that sedentary time in childhood induces pathological changes in the heart’s left ventricle, but light activity can mitigate these harmful effects. Moderate-to-vigorous activity, however, induces beneficial physiological changes. Resistance training is a safe and effective way to boost kids' activity levels. Learn more about kids and resistance training in this clip featuring Dr. Brad Schoenfeld.
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