Turn up the healthy eating and activity time (HEAT): Physical activity outcomes from a 4-year non-randomized controlled trial in summer day camps

•Over 14 million children attend summer day camps each year.•Camps are well positioned to help children meet physical activity guidelines.•This study evaluates a multi-summer physical activity intervention in 20 camps.•Without intervention, children achieve high amounts of physical activity at camp.•Efforts should focus on making summer day camps accessible to all children. Summer day camps (SDCs) serve over 14 million children in the U.S. and are well-positioned to help children accumulate the guideline of 60 min per day (60 min/d) of moderate-to-vigorous physical activity (MVPA). The purpose of this study was to evaluate a multi-component intervention to increase the percentage of children meeting 60 min/d of MVPA. Twenty SDCs serving 3524 children (7.9 yrs., 46.2% girls, 66.1% non-Hispanic Black) participated in a 4-summer non-randomized two-group intervention. Children’s accelerometer-derived MVPA was collected using accelerometers worn on the non-dominant wrist. SDCs were assigned to either 2 summers of intervention (n = 10, no intervention summer 2015, intervention summer 2016 and 2017) or 1 summer of intervention (n = 10, no intervention summer 2015 and 2016, intervention summer 2017). The final summer (July 2018) was a no intervention follow-up. Multilevel mixed effects regression models estimated changes in percent of children meeting 60 min/d of MVPA. Across all summers and SDCs, children accumulated an average of 89.2 min/day (±22.5) of MVPA. The likelihood of meeting the 60 min/d MVPA guideline was not different during intervention versus baseline summers for boys or girls (p > 0.05). Girls and boys were 3.5 (95CI = 1.5, 8.1) and 3.7 (95CI = 1.6, 8.4) times more likely to meet the 60 min/d guideline during intervention summers versus follow-up, respectively. The intervention was not successful at increasing the percentage of children meeting the 60 min/d MVPA guideline. However, children attending SDCs accumulated substantial amounts of MVPA thus efforts should focus on making SDCs an accessible setting for all children.