Health / Health News |
Children who walk to school less likely to be overweight or obese, study suggests
Based on results from more than 2000 primary-age schoolchildren from across London, the researchers found that walking or cycling to school is a strong predictor of obesity levels, a result which was consistent across neighbourhoods, ethnicities and socioeconomic backgrounds.
The study is the first to assess the impact of physical activity on childhood overweight and obesity levels for primary schoolchildren by simultaneously relating two of the main types of extracurricular physical activity: daily commuting to school and frequency of participation in sport.
Instead of using Body-mass index (BMI) as a measure of obesity, the researchers measured body fat and muscle mass and assessed how these were correlated with physical activity levels. BMI is the most commonly-used metric to measure obesity levels due to its simplicity, however, it is limited as BMI looks at total weight, including ‘healthy’ muscle mass, rather than fat mass alone.
The current research is based on data from the Size and Lung Function in Children (SLIC) study, carried out at University College London between 2010 and 2013. More than 2000 London primary schoolchildren, from a range of ethnic and socioeconomic backgrounds, were included in the study, which looked at their physical activity levels, body composition and socioeconomic status.
Close to half of children in the study took part in sport every day, and a similar proportion actively commuted to school, travelling on foot, by bicycle or scooter. The researchers found that children who actively commuted to school had lower body fat, and therefore were less likely to be overweight or obese.
Paradoxically, using conventional BMI percentiles, children who took part in sport every day appeared more likely to be overweight or obese than those who engaged in sport less than once a week. However, when looking at fat mass and muscle mass separately, children who engaged in sport every day had significantly more muscle development, while their fat mass did not significantly differ.
The link between frequent participation in sport and obesity levels has generated inconsistent findings in previous research, but many of these studies were looking at BMI only. However, when looking at body fat instead, we showed there was a trend whereby children who were not active were more likely to be overweight or obese. It’s likely that when looking at BMI, some inactive children aren’t classified as obese due to reduced muscle mass. (University of Cambridge)