Advancing the global physical activity agenda: recommendations for future research by the 2020 WHO physical activity and sedentary behavior guidelines development group.

Background In July, 2019, the World Health Organization (WHO) commenced work to update the 2010 Global Recommendations on Physical Activity for Health and established a Guideline Development Group (GDG) comprising expert public health scientists and practitioners to inform the drafting of the 2020 Guidelines on Physical Activity and Sedentary Behavior. The overall task of the GDG was to review the scientific evidence and provide expert advice to the WHO on the amount of physical activity and sedentary behavior associated with optimal health in children and adolescents, adults, older adults (> 64 years), and also specifically in pregnant and postpartum women and people living with chronic conditions or disabilities. Methods The GDG reviewed the available evidence specific to each sub-population using systematic protocols and in doing so, identified a number of gaps in the existing literature. These proposed research gaps were discussed and verified by expert consensus among the entire GDG. Results Evidence gaps across population sub-groups included a lack of information on: 1) the precise shape of the dose-response curve between physical activity and/or sedentary behavior and several of the health outcomes studied; 2) the health benefits of light-intensity physical activity and of breaking up sedentary time with light-intensity activity; 3) differences in the health effects of different types and domains of physical activity (leisure-time; occupational; transportation; household; education) and of sedentary behavior (occupational; screen time; television viewing); and 4) the joint association between physical activity and sedentary time with health outcomes across the life course. In addition, we acknowledge the need to conduct more population-based studies in low- and middle-income countries and in people living with disabilities and/or chronic disease, and to identify how various sociodemographic factors (age, sex, race/ethnicity, socioeconomic status) modify the health effects of physical activity, in order to address global health disparities. Conclusions Although the 2020 WHO Guidelines for Physical Activity and Sedentary Behavior were informed by the most up-to-date research on the health effects of physical activity and sedentary time, there is still substantial work to be done in advancing the global physical activity agenda. In July, 2019, the World Health Organization (WHO) convened a group of public health scientists and practitioners to serve on the Guidelines Development Group (GDG) for the 2020 Guidelines on Physical Activity and Sedentary Behavior [1]. The GDG comprised 27 physical activity experts from selected disciplines (epidemiology, physiology, health behavior, etc.), as well as policy makers and end-users of the recommendations and was balanced by global region and by gender. The overall task of the GDG was to review the scientific evidence and provide expert advice to the WHO on the amount of physical activity and sedentary behavior associated with optimal health in children and adolescents, adults, older adults (> 64 years), and also, specifically in pregnant and postpartum women and people living with chronic conditions or disabilities. These 2020 Guidelines (as well as those for children ages 0–5 years) [2] replace the recommendations released by the WHO in 2010 [3], as they include the most current evidence available across a broader life course. For children and adolescents (aged 5–17 years) the current reviews updated the evidence syntheses conducted for the 2016 Canadian 24-Hour Movement Guidelines for Children and Youth [4,5,6], the 2019 Australian 24-Hour Movement Guidelines for Children and Young People (5–17 years) [7] and the Physical Activity Guidelines for Americans, 2nd edition that were released in 2018 [8]. For adults, older adults and sub-populations, the reviews updated evidence syntheses conducted for the Physical Activity Guidelines for Americans, 2nd edition [8] and the 2019 Canadian Guidelines for Physical Activity Throughout Pregnancy [9]. Systematic reviews published from 2017 to July 2019 were identified that addressed the key questions, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework was used to rate the certainty of the evidence. Full details of the methods for identifying the most current evidence to inform these 2020 Guidelines are described in detail elsewhere [10]. While reviewing the available evidence to inform the 2020 Guidelines, the GDG identified a number of gaps in the existing literature, many of which were carried forward from our earlier work on the Australian [7], Canadian [4,5,6, 9], and United States [8] Guidelines. These proposed research gaps were discussed and verified by expert consensus among the entire GDG. Below, we describe the research gaps according to the different population sub-groups investigated, along with research recommendations that could advance the global physical activity agenda and future public health practice. These research recommendations are listed in Tables 1 and 2.