Sedentary Lifestyles in Children Can Have Massive Consequences
The most iconic moment in the popular Dr. Seuss children’s story How the Grinch Stole Christmas comes when the narrator declares “the Grinch’s small heart grew three sizes that day.” The implied point is that the Grinch’s affections toward towards his neighbors grew in love and charity, not that he was suddenly unhealthy and at risk for hypertension.
However, a new study found that sitting around too much can produce the latter in young children. Staying active is one of the best ways to keep a healthy heart, so it should come as no surprise that sedentary habits have harmful consequences.
Researchers at the University of Bristol in the UK, the University of Exeter in the UK, and the University of Eastern Finland found that “sedentary time may increase heart size three times more than moderate-to-vigorous physical activity,” according to Science Daily. The site provided the following summary of the findings:
The current 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 8 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 (3.8 g/m2.7) associated with sedentary time was three times higher than the cardiac mass increase (1.2 g/m2.7) 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.
The U.S. Department of Health and Human Services recommends children ages 6 and up should get “at least 60 minutes per day of moderate- to vigorous-intensity physical activity, mostly aerobic,” including vigorous and intense exercise at least three days each week.