Walking to school may decrease stress reactivity, improve cardiovascular health

Lambiase MJ. Med Sci Sports Exerc. 2010;doi:10.1249/MSS.0b013e3181d0c77b.

A child who walks to school may not only experience less cognitive stress throughout the day but may also reap the benefits of decreases in heart rate and blood pressure later in life, recent study data indicate.

“Children must cope with many social and cognitive stressors during a school day, including peer relationships, making friends, teasing, and completion of coursework and homework,” wrote researchers from the University at Buffalo, in New York.

“The perception of a stressor as a threat is the beginning of the stress reactivity process, so if you can dampen that initial perception, then you reduce the magnitude of the fight-or-flight response,” study researcher James Roemmich, MD, PhD, said in a press release. “We know that physical activity has a protective effect on the development of cardiovascular disease, and one way it may be doing so is by reducing stress reactivity.”

The researchers’ goal was to investigate the effect that a simple increase in physical activity, such as walking to school, would have on the cardiovascular health of children and their functioning throughout the school day.

Twenty white girls and 20 white boys participated in the study. Children were free of conditions or diseases that would affect physical activity and had no history of diagnosed psychiatric disorder. They also were not taking medications that would change baseline stress or stress reactivity.

All participants had BMIs less than the 85th percentile, the researchers said, and none walked to school more than 1 day per week.

Children were randomly assigned to one of two groups: a sedentary set of children who sat in chairs during a slideshow of digital photographs designed to simulate a ride to a suburban school or an active set of children who experienced the same scenery while walking at their own pace on a treadmill. Those walking also carried a backpack that was 10% of their own weight.

The researchers then measured cardiovascular stress while the children completed the Stroop task test.

According to study results, the following appeared lower in the walking group when compared with the control group: heart reactivity (P<.001), systolic BP (P<.001), pulse pressure reactivity (P<.001) and perceived stress (P<.001).

Although these data are promising, Roemmich said how long the protective benefits of exercise last are still unclear.

“If it only last a couple of hours, then it would be most beneficial if a child walked or biked to school, then had recess during school, as well as a break at lunch, so they had opportunities for physical activity throughout the day,” he said. “This would put them in a constantly protective state against stressors that they’re incurring during the school day, whether that be taking an exam, trying to fit in with peers or speaking in front of classmates.”

The researchers also noted that children may experience other health benefits, such as improved cognitive function and academic performance, as a result of increased physical activity.

The researchers also noted certain study limitations that prevented them from making more definitive conclusions, such as the between-subjects research design, restricted sample size and the fact that it was laboratory-based. Results may have been different if the study took place in a school setting, they said.

Additionally, the study population lacked diversity, which further limited the study findings, according to the researchers, and the short timeline may have interfered with the results.

They also said, however, that future research should include minorities, as their results may be limited by the homogenous study cohort.

Social implications are clear, and require rigorous testing before accepting such a tantalizing and in many ways a hoped for conclusion — that if we have children exercise more, and not necessarily vigorously, they will be healthier mentally as well as physically. Planned residential communities from the 1960's to today have included designs to accomodate walking to and from school (and in the 60's home for lunch in an era where mother's more frequently remained at home). In fact, paths were designed to minimize crossing streets on the way to centrally placed elementary schools. Clearly, some areas of the country are unlikely to be able to provide a safe and relaxing environment for travel to and from school. Nevertheless, if indeed supported by further research, community-based efforts could be designed and supported to allow for increased walking among our youth. At least a potentially important finding in a field which is not directed at a pharmaceutical solution.

– William T. Gerson, MD
Infectious Diseases in Children Editorial Board Member

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