TUESDAY, Aug. 16, 2005 (HealthDayNews) -- American parents concerned about raising 'couch potato' kids might want to rethink driving or busing their children to school: A new study found the simple act of walking to school greatly increased the amount of exercise a child got each day.
Not surprisingly, compared with adolescents who take a bus, car or train to and from school, those who walk got lots more physical activity, according to a Scottish report published in the Aug. 16 online issue of the British Medical Journal.
"Traffic jams outside schools with parents and guardians dropping young people off aren't doing anyone any good," said study author Leslie Alexander, an honorary fellow in public health sciences at the University of Edinburgh. "We found that people who walked both ways to school accrued the most minutes of moderate to vigorous physical activity throughout the entire day," she added.
In their study, Alexander and her colleagues measured physical activity in 92 Scottish students aged 13 and 14.
To measure physical activity, students wore hip accelerometers, which measure vertical movement, throughout the day. Alexander's team divided the students into three groups: those who went to school both ways by car, bus or train, those who walked both ways, and those who walked just one way.
Alexander's group found that students who walked both ways had the most moderate-to-vigorous physical activity. They were followed by those walking one way. Those who took a bus, car or train had significantly less physical activity.
The researchers point out that the walk to and from school wasn't the sole source of extra activity in kids who used their feet to make it to class. "These young people who walked to school accrued more minutes of physical activity while at school, which by definition excludes their travel time," Alexander said.
Her team found that 87 percent of the students who traveled by car, bus or train averaged 60 minutes or more of moderate to vigorous physical activity per weekday, compared with 90 percent of the students who walked one way and 100 percent of the students who walked both ways.
"People who walked both ways accrued more minutes of physical activity during their morning break, and during their lunch break, and during the day as a whole," Alexander said.
There's no doubt that walking is good for the body, Alexander said. "Trust your legs and take time to walk to school," she said. "Even walking one way will boost the amount of activity we get during the day."
Physical activity is a habit that begins early in life, Alexander noted. "There is some evidence that our activity levels from when we are young can be used as predictors for our activity levels as we get older," she said. "It's unlikely that there is any biological reason for this. So we can decide to get up and move at anytime."
One expert believes the study addresses a larger societal problem.
"Declining physical activity levels in children over recent decades are associated with the rising rates of obesity and diabetes seen in this population," said Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine.
Much of the reduction in energy expenditure has to do with social and environmental engineering, Katz said. "Longer work days mean fewer hours of family activity each day. More technology means more sedentary recreation. Suburban sprawl means car use for all transportation. And even the time-honored walk to school has been engineered out of our neighborhoods, and our lives."
Why children who walk to school get more exercise is not clear, Katz said. "Is this because health-conscious children walk to school, or because walking to school promotes more physical activity overall?"
"This study can't say, and one might infer it's a bit of both," he said. "But certainly the association is enough to invite misgivings about the ways we are engineering physical activity out of our lives and the lives of our children. Research such as this may help us to recognize, and reverse, this adverse trend."
The U.S. Centers for Disease Control and Prevention can tell you more about the importance for children of physical activity.