Study links childhood inactivity with heart enlargement, finds light activity could reverse effects

New Delhi: Being sedentary or performing little activity in childhood is associated with heart enlargement, which progressed with an increase in time spent sitting or being inactive, according to new research.

An excessive increase in heart mass and size, known as left ventricular hypetrophy, is a known risk factor for heart attacks, stroke and premature death in adults.

However, light physical activity of about three or four hours a day, including running errands and playing outdoor games, was found to reverse the increase in heart mass, with more of such activity being associated with better cardiac function, according to researchers who observed child and adolescent participants for 13 years.

"There is growing evidence that childhood sedentariness is a health threat that needs to be taken seriously," Andrew Agbaje, a physician and an associate professor of clinical epidemiology and child health at the University of Eastern Finland, said.

"There must be a paradigm shift in how we view childhood sedentariness, as the mounting evidence is pointing at a ticking time bomb," Agbaje, the author of the study published in the European Journal of Preventive Cardiology, said.

For the study, the researchers followed nearly 1,700 children from the UK's University of Bristol's 'Children of the 90s cohort' from age 11 until 24 years. At the start of the study, the children spent about six hours a day performing sedentary activities, which increased to nine hours a day as they became young adults.

The participants wore accelerometer devices (for tracking movement) on their waists at ages 11, 15, and 24 years for a duration of 4-7 days and had echocardiography measurements taken of their heart structure and function at ages 17 and 24 years.

Other aspects like lifestyle factors and socio-economic status were also analysed, along with fasting blood samples for cholesterol, glucose, insulin and C-reactive protein -- an indicator of inflammation.

The researchers found that over a period of seven years, during which the adolescents grew into young adult, the heart enlargement associated with the increase in sedentary time contributed 40 per cent to the total increase in heart mass.

Being sedentary or inactive was found to increase heart mass, regardless of obesity or elevated blood pressure status.

The team also found that light physical activity over the entire follow-up period reduced the increase in heart mass by about half.

"LPA is an effective antidote to sedentariness. It is easy to accumulate three to four hours of LPA daily.

"Examples of LPA are outdoor games, playing in the playground, walking a dog, running errands for parents, walking and biking to the shopping mall or to school, taking a stroll in the park, playing in the forest, gardening, casual basketball, soccer, floorball, golf, frisbee, etc. We can encourage children and adolescents to participate in LPA daily for better cardiovascular health," Agbaje said.