A sedentary lifestyle in childhood increases the risk of progressing left ventricular hypertrophy, a heart enlargement condition that raises the likelihood of heart attacks, stroke, and premature death in adulthood, a study revealed.

To reverse the risk of increasing heart mass and size, light physical activity every day, for just three to four hours could help, according to the latest study from the research team involving researchers from the Universities of Bristol and Exeter in England and the University of Eastern Finland.

The research team followed up 1,682 children who were part of the University of Bristol's Children of the 90s cohort for around 13 years, from the age of 11 until they reached 24. The participants wore accelerometer devices on their waists for 4–7 days at three stages: at ages 11, 15, and 24 years. To measure the heart structure and function, researchers took echocardiography of the participants at ages 17 and 24.

The blood samples of the participants were taken at various stages to measure low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), triglycerides, glucose, insulin, and high-sensitivity C-reactive protein. The study also accounted for factors such as participants' blood pressure, heart rate, smoking status, socio-economic status, and family history of cardiovascular disease.

The average sedentary time during the baseline was six hours per day which gradually increased to nine hours per day by the time they reached young adulthood.

"This increase in sedentary time was associated with progressing heart enlargement, contributing 40% to the total increase in heart mass within a 7-year growth period from adolescence to young adulthood. Sedentariness increased heart mass regardless of obesity or elevated blood pressure status," the news release stated.

However, the researchers noted that an average of three to four hours per day of light physical activity during the follow-up period reduced the increase in heart mass by 49%. With higher amounts of light physical activity, there was better cardiac function.

Meanwhile, with moderate-to-vigorous physical activity, there was a slight increase in heart size (5%) which is mainly physiologic, the researchers said.

"There is growing evidence that childhood sedentariness is a health threat that needs to be taken seriously. There must be a paradigm shift in how we view childhood sedentariness, as the mounting evidence is pointing at a ticking time bomb," said Andrew Agbaje who led the research.

"Light physical activity (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," he added.

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