Sedentary time may significantly enlarge adolescents’ heart

Newswise —

According to a research paper published in the Scandinavian Journal of Medicine & Science in Sports, sedentary behavior during adolescence may result in a threefold increase in heart size compared to moderate-to-vigorous physical activity. The study was a collaborative effort between the University of Bristol and the University of Exeter in the UK, as well as the University of Eastern Finland. The researchers examined the links between sedentary time, light physical activity, and moderate-to-vigorous physical activity, and their effects on cardiac structure and function.

The World Health Organization has recently highlighted that over 80% of adolescents worldwide do not engage in sufficient physical activity on a daily basis, as per their reports and guidelines. Physical inactivity has been linked to various non-communicable diseases in adults, including cardiovascular diseases, type 2 diabetes, and cancer. While research on movement behavior in the pediatric population has largely focused on the impact of sedentary behavior and physical activity on cardiometabolic health indicators such as blood pressure, insulin resistance, blood lipids, and body mass index.

There is a significant knowledge gap when it comes to understanding the impact of sedentary behavior and moderate-to-vigorous physical activity on cardiac structure and function in large populations of adolescents. This gap arises due to limited availability of device-measured movement behavior data and echocardiography assessments in the pediatric population. Enlarged or hypertrophied heart, as indicated by higher left ventricular mass, along with reduced left ventricular function, can independently or collectively increase the risk of heart failure, myocardial infarction, stroke, and premature cardiovascular death.

The present study utilized data from the renowned University of Bristol study known as Children of the 90s, also referred to as the Avon Longitudinal Study of Parents and Children. The study sample consisted of 530 adolescents who were 17 years old and had comprehensive measurements of various health indicators including fat mass, muscle mass, glucose levels, lipids, inflammation markers, insulin levels, smoking status, socio-economic status, family history of cardiovascular disease, as well as echocardiographic assessments of cardiac function and structure. Additionally, accelerometer-based measures were used to capture sedentary time, light physical activity, and moderate-to-vigorous physical activity levels.

According to the findings of this recent study, adolescents, on average, spent nearly 8 hours per day engaged in sedentary behavior and approximately 49 minutes per day in moderate-to-vigorous physical activity. Both sedentary time and moderate-to-vigorous physical activity were found to be associated with increased left ventricular mass. However, the increase in cardiac mass (3.8 g/m2.7) linked to sedentary time was three times higher than the increase (1.2 g/m2.7) associated with moderate-to-vigorous physical activity. Interestingly, this pattern was observed regardless of the adolescents' obesity status, including those who were of normal weight, overweight, or obese. Notably, light physical activity was not found to be associated with an increase in cardiac mass, but it was linked to improved cardiac function as estimated from left ventricular diastolic function.

"This novel evidence expands our understanding of the detrimental impact of sedentary time on cardiac health, particularly in adolescents. Previous research has shown that even a modest increase of 5 g/m2 in cardiac mass can raise the risk of cardiovascular disease and mortality by 7 to 20% in adults. While engaging in moderate-to-vigorous physical activity may also result in slight enlargement of the heart, the multiple health benefits associated with such exercise outweigh this acceptable negative side effect. Therefore, it is crucial for public health experts, health policymakers, high school administrators and teachers, pediatricians, and caregivers to actively promote and facilitate adolescent participation in physical activity to promote a healthy heart," emphasized Andrew Agbaje, a physician and clinical epidemiologist at the University of Eastern Finland.

Dr. Agbaje's research group, urFIT-child, is grateful for the generous support from various research grants. These grants are provided by esteemed organizations such as the Jenny and Antti Wihuri Foundation, the Finnish Cultural Foundation Central Fund, the Finnish Cultural Foundation North Savo Regional Fund, the Orion Research Foundation sr, the Aarne Koskelo Foundation, the Antti and Tyyne Soininen Foundation, the Paulo Foundation, the Yrjö Jahnsson Foundation, the Paavo Nurmi Foundation, the Finnish Foundation for Cardiovascular Research, and the Foundation for Pediatric Research. The support from these foundations has been instrumental in advancing the research on the impact of physical activity on cardiac health in adolescents conducted by urFIT-child.