Reversing High Cholesterol Caused By Childhood Sedentariness With Light Physical Activity

W.H.O. recommends that children/adolescents should accumulate 60 minutes of moderate to vigorous physical activity every day and reduce sedentary time, but the organization has limited guidelines for light physical activity. 

Prevention is better than cure, as such healthy lifestyles (which includes diet and movement behavior) are considered to be important in the prevention of dyslipidemia and one of the primary ways of lowering cholesterol. This study objectively examined the long-term effects of sedentary time, light physical activity, and moderate to vigorous physical activity on childhood cholesterol levels. 

This study and another study led by Dr. Andrew Agbaje recently published in Nature Communications have found that light physical activity such as long walks, household chores, dancing, swimming, or cycling is up to 5 times more effective than moderate to vigorous physical activity at promoting heart health and lowering inflammation in younger populations. 

Researchers working in collaboration from the University of Exeter, the University of Eastern Finland, and the University of Bristol utilized data from the University of Bristol study Children of the 90s (also known as the Avon Longitudinal Study of Parents and Children) that included 792 eleven-year-old children who were followed until the age of 24 years old. 

Findings showed that accumulated sedentary time from childhood increased cholesterol levels by 67% by the time the participants reached their mid-twenties. Elevated cholesterol and dyslipidemia from childhood/adolescence have been associated with premature death in those in their mid-forties, as well as heart problems such as subclinical atherosclerosis and cardiac damage among those in their mid-twenties. 

“These findings emphasise the incredible health importance of light physical activity and shows it could be the key to preventing elevated cholesterol and dyslipidaemia from early life. We have evidence that light physical activity is considerably more effective than moderate-to-vigorous physical activity in this regard, and therefore it's perhaps time the World Health Organization updated their guidelines on childhood exercise -- and public health experts, paediatricians, and health policymakers encouraged more participation in light physical activity from childhood,” said Dr. Andrew Agbaje from the University of Exeter.

For this study, accelerometer measures of sedentary time, light physical activity, and moderate-to-vigorous physical activity were collected at ages 11, 15, and again at 24 years of age. High-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, and total cholesterol were repeatedly measured at ages 15, 17, and at 24 years old. These participants also had repeated measurement of dual-energy X-ray absorptiometry assessment of total body fat mass and muscle mass, as well as fasting blood glucose, insulin, and high sensitivity C-reactive protein, with smoking status, socio-economic status, and family history of cardiovascular disease.

The researchers found that sedentary time increased from around 6 hours per day to nine hours a day, and light physical activity decreased from 6 hours a day to three hours a day while moderate-to-vigorous physical activity was relatively stable at around 50 minutes a day from childhood until young adulthood during the 13 year follow up period. Additionally, the average increase in total cholesterol was 0.69 mmol/l, and it was observed without any influence from body fat during the follow-up period. 

According to the researchers (urFIT-child), an average of four-and-a-half hours a day of light physical activity from childhood through young adulthood causally decreased total cholesterol by (-0.53 mmol/l), however, body fat mass could reduce the effect of light physical activity on total cholesterol by up to 6%. Around 50 minutes a day of moderate-to-vigorous physical activity from childhood was also associated with slightly reduced total cholesterol (-0.05 mmol/L), but total body fat mass decreased the effect of moderate-to-vigorous physical activity on total cholesterol by up to 48%. Importantly, the increase in fat mass neutralized the small effect of moderate-to-vigorous physical activity on total cholesterol.

Findings from the other study published in Nature Communications found that light physical activity may completely reduce childhood obesity linked to increased sedentary time in over 6000 children, and that sedentary time contributed to 7-10% of the total fat mass gained during growth from childhood until young adulthood. However, light physical activity decreased the overall gain in fat mass by 9.5-15%, while moderate to vigorous physical activity decreased fat mass by only 0.7-1.7%.

"Our research suggests light physical activity may be an unsung hero and it is about time the world replaced the mantra of 'an average of 60 minutes a day of moderate-to-vigorous physical activity' with 'at least 3 hours a day of light physical activity'. Light physical activity appears to be the antidote to the catastrophic effect of sedentary time in the young population,” said Dr. Andrew Agbaje.