Children who walk or cycle to school may have a healthier body weight than those who arrive by car. A study followed more than 8,000 schoolchildren over a period of years. The findings showed that even using public transport instead of taking the car led to a reduction in body fat.
It is widely accepted that physical activity helps people of all ages stay at a healthy weight. Walking or cycling to school (active travel) is likely to help children achieve this but, before this study, there was a lack of adequate evidence tracking children over time to support this claim.
As children get older, they become more independent and often have more choices about how they get to school. Researchers found that children who switched to walking and cycling to school between the ages of 7 and 14 had healthier body weights than those who continued to travel by car. The findings also suggest that the beneficial effects of walking or cycling may be greater for children from the most deprived areas.
Obesity is a major public health problem in the UK. More than one in five children in the last year of primary school are overweight and as a result are likely to have poorer physical and mental health.
This research underlines the importance of encouraging active travel. This means providing safe and effective infrastructure to encourage people to walk, cycle, or use public transport. Finding ways of supporting children and families from lower income households to walk or cycle could help these groups overcome some of the health inequalities they face.
Obesity is becoming more common in the UK, particularly among disadvantaged groups. Children living in the most deprived areas are more than twice as likely to be overweight than children living in the least deprived areas.
Being obese or overweight is linked to poor mental health. Children living with obesity are more likely to be overweight as adults. This increases their risk of medical conditions such as diabetes and heart disease, of disability, and early death.
Physical activity can help children stay at a healthy weight. But less than half of children and young people meet the recommended level of physical activity of an hour each day.
Getting around by walking, cycling and other active methods of transport is one way of increasing physical activity. The choices and options of transport available to children change as they grow up and become more independent. Options such as walking are available to children from a range of backgrounds and may offer a way of combating health inequalities.
Our research and why it is useful
While it seems likely that active travel to school could help children maintain a healthy weight, there is a lack of adequate evidence. The researchers wanted to look for links between how children and young people travel to school and their weight over the long-term. The research team used the UK Millennium Cohort Study to follow the same children over 8 years. They gathered data on 8,432 children at the ages of 7, 11 and 14.
Researchers asked families and caregivers whether their child usually travelled to school by car or other vehicle (including taxi), public transport, bicycle, or walking. They used two ways of measuring how healthy the children’s weight was: the percentage of body fat, and Body Mass Index (BMI), which takes into account weight and height.
They also analysed information about other factors that may influence the relationship between weight and travel type. This included data on sex, ethnicity, socioeconomic background, whether children ate breakfast, and other physical activity.
More than half the children switched their way of getting to school at least once. At age 14, one in four (26%) went by car, one in three (35%) by public transport, and the largest group (39%) walked or cycled.
Children who switched to active transport between the ages of 7 and 14 had healthier body weights than those who continued to travel by car. A greater number of children from lower-income households walked or cycled to school. The data suggested that these children benefited more from the switch than children from wealthier backgrounds, but the difference was slight.
Compared with continuing to use private transport, the group which switched to walking or cycling had:
- less body fat (0.55% less on average)
- a lower BMI (0.21 kg/m² less on average)
Switching to public transport was associated with slightly less body fat (average reduction of 0.43%) but no meaningful reduction in BMI.
“The results add to lots of other evidence on the health benefits of walking, cycling and public transport.
In particular, our findings add evidence that changing travel mode at a key period in a young person’s life can have health benefits. We know that from age 7 to 14 there are lots of big changes in children’s lives, including changing schools and the likely onset of puberty. But the results tell us that what is a simple change for many people can have demonstrable benefits.
It may also be that the beneficial effects of switching to walking or cycling are greater for children from lower-income households. This is important if true, because lots of existing interventions tend to give more benefit to more advantaged people.
I hope that all of this evidence will encourage individuals to consider changing their travel behaviours. But more importantly, there is a big role for local and national governments to make it easier for people to walk and cycle. There has been a real focus on this throughout the COVID-19 pandemic, with more cycle lanes and infrastructure being built for example, so hopefully this can continue.”
Anthony Laverty, Member of the NIHR School for Public Health Research, Imperial College London
The researchers note that active travel is only one potential route to a healthy weight. Other lifestyle changes (switching to eating breakfast every day or taking part in sport five or more days/week) were linked to greater reductions in BMI and body fat. But they say that active travel is a simple and widely available lifestyle change.
This research adds to evidence advocating for the health impacts of active travel. In addition to the environmental benefits, these findings suggest that children can achieve a healthier body weight by switching to physically active forms of travel.
Disadvantaged children may benefit more than others from his lifestyle change. Interventions to increase the amount of active travel these children do could help them overcome the health inequalities they face as a result of their socioeconomic background.
The researchers say that further evidence is needed on how best to encourage people to use active modes of travel rather than using the car.
This will require action at a number of levels. School policies to discourage driving would help, as would safer cycle routes. Policy changes could include expansions to London’s Congestion Charge scheme, Low Emission Zones in other places like Birmingham, and the implementation of Low Traffic Neighbourhoods.
The researchers conclude that ambitious thinking is needed to drive and support positive changes in travel behaviour.
This research has been published in the following paper: Laverty AA, and others. Associations of active travel with adiposity among children and socioeconomic differentials: a longitudinal study. BMJ Open 2021;11:e03604
This impact case study was originally published as a NIHR Evidence Alert. A link to this publication can be found here.