The following is excerpted from an online article posted by MedicalXpress.
In adolescents, sedentary time may increase heart size three times more than moderate-to-vigorous physical activity, a paper published in the Scandinavian Journal of Medicine & Science in Sports concludes. The study was conducted in collaboration between the University of Bristol in the U.K., the University of Exeter in the U.K., and the University of Eastern Finland. The researchers explored the associations of sedentary time, light physical activity, and moderate-to-vigorous physical activity with cardiac structure and function.
The study, which used data from the University of Bristol study Children of the 90s (also known as the Avon Longitudinal Study of Parents and Children), included 530 adolescents aged 17 years who had complete measurements of fat mass, muscle mass, glucose, lipids, an inflammation marker, insulin, smoking status, socio-economic status, family history of cardiovascular disease, echocardiographic cardiac function and structure measures, and accelerometer-based measure of sedentary time, light physical activity, and moderate-to-vigorous physical activity.
On average, adolescents spent almost eight hours/day sedentary and about 49 minutes/day in moderate-to-vigorous physical activity in this new study. It was observed that both sedentary time and moderate-to-vigorous physical activity were associated with higher left ventricular mass. However, the increase in cardiac mass associated with sedentary time was three times higher than the cardiac mass increase associated with moderate-to-vigorous physical activity. This finding was observed in adolescents irrespective of their obesity status, i.e., among adolescents who had normal weight and those who were overweight or obese. Importantly, light physical activity was not associated with an increase in cardiac mass but was associated with better cardiac function estimated from left ventricular diastolic function.
“This novel evidence extends our knowledge of the adverse effects of sedentary time on cardiac health. It is known among adults that an increase in cardiac mass may increase the risk of cardiovascular disease and death by 7%–20%. Engaging in moderate-to-vigorous physical activity also slightly enlarged the heart, but it seems an acceptable ‘negative side effect’ considering several other health benefits of moderate-to-vigorous exercise,” says Andrew Agbaje, a physician and clinical epidemiologist at the University of Eastern Finland.