Children who walk to school or cycle are less likely to be overweight or obese, compared to those who get there by car or public transport, according to a new study.
The survey by researchers from the University of Cambridge is the first to assess the impact of physical activity on childhood overweight and obesity levels for primary schoolchildren. It simultaneously related two of the main types of extracurricular physical activity: Daily commuting to school and frequency of participation in sport.
The findings - published in the journal BMC Public Health - are relevant for Kenyan parents, some who take their children to school using their cars or pay dearly for school public transport operators to have their children ferried school.
Data from Kenya National Bureau of Statistics (KNBS) economic survey 2019 shows that parents pay between Sh3,000 and Sh10,000 per term for school transport. For those using their cars, they have to contend with high fuel prices that currently stand at between Sh100 and Sh120 for diesel and petrol respectively.
The researchers evaluated 2,000 primary-age schoolchildren from across London and found out that walking or cycling to school was a strong predictor of obesity levels, a result which was consistent across neighbourhoods, ethnicities and socio-economic backgrounds.
The researchers measured body fat and muscle mass and assessed how they correlated with physical activity levels instead of using body-mass index (BMI) as a measure of obesity.
Medical experts say BMI is the most commonly used metric to measure obesity levels due to its simplicity, though it is limited, as it looks at total weight, including “healthy” muscle mass, rather than fat mass alone.
“Both BMI itself and the points at which high BMI is associated with poor health vary with age, sex and ethnicity,” said Lander Bosch, a PhD candidate in Cambridge’s Department of Geography, and the study’s first author.
Bosch said while adjustments had been made in recent years to account for these variations, BMI remains a flawed way to measure the health risks associated with obesity.
The latest research is based on data from the Size and Lung Function in Children study, carried out at University College London between 2010 and 2013. Researchers said half of the children in the study took part in sport every day, and a similar proportion actively commuted to school, getting there on foot, by bicycle or scooter.
They 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, the study shows, 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, Bosch said, 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,” said Bosch. When looking at body fat instead, Bosch said children who were not active were more likely to be overweight or obese.