As the prevalence of childhood obesity continues to worsen in the U.S., one Washington State University researcher believes outdoor preschools may be key to curbing this trend at an early age.

Amber Fyfe-Johnson, a WSU assistant research professor and former pediatrician, suggested that those who are overweight or obese at a young age often struggle to augment that trajectory through adulthood, increasing their risk for a number of health issues later in life, including heart disease.

While there are good data linking outdoor instruction to positive social-emotional, academic and behavioral health outcomes, Fyfe-Johnson said the practice’s effect on physiological health is relatively understudied.

In a bid to remedy that, she will embark on a five-year study, funded by the National Institutes of Health and the George B. Storer Foundation, of children attending Tiny Trees — a Seattle-area outdoor preschool and the largest program of its kind in the country. Past studies have found that children are almost twice as active when playing in an outdoor space versus an indoor space, which is encouraging for general health and obesity prevention, she said.

Nonetheless, very little is known about physical activity in exclusively outdoor preschools.

“The health outcomes that I’m interested in are sleep, (body mass index), and gut microbiome health,” Fyfe-Johnson said. “I’m also very seriously considering adding myopia — so nearsightedness — because there’s some evidence that outdoor time prevents myopia.”

She said she will also measure physical activity with wearable devices.

Fyfe-Johnson said 200 children will be included in the study — 100 who are attending Tiny Trees and another 100 from the school’s waitlist who are attending a range of more traditional preschools that will act as a control group. She said during the study, she will follow three cohorts of children for two years each, collecting data at the beginning and the end of each school year.

Fyfe-Johnson said she anticipates that BMI will be maintained in a healthy range for all participants, but expects sleep quality and gut microbiome health to improve. She said sleep quality will likely rise in part because increased activity will allow children to go to bed tired. As for benefits to the gut microbiome, she said just playing outside will expose children to a more diverse array of microbes than if they spend the majority of their time in a sanitized classroom setting.

Darci Deaton, director and lead teacher for Moscow-based outdoor school Palouse Roots, said beyond the school’s direct effect on health, outdoor instruction also imparts a lifelong inclination toward a healthy level of outdoor activity.

“I think they walk away from a year at outdoor school, feeling really comfortable in the outdoors,” Deaton said. “I’m sure it carries with them as they grow older and into their adulthood — so they end up spending more time outside than perhaps their peers.”

While her research promises to break new ground, Fyfe-Johnson said this study is only the beginning. She said she hopes to use data generated through this work to make the case to fund expanding the study to more schools across the country and to monitor children through third grade and possibly beyond.

“I’d really like to stay with these children longer and so I’m going to use the first cohort to try and do just that — try and get funding to follow them for a longer period,” Fyfe-Johnson said. “I would love to follow these kids longer than third grade, that would be my dream job — whether or not somebody who has money to give to a project like that shares those sentiments remains to be determined.”

Scott Jackson can be reached at (208) 883-4636, or by email to

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