Challenges in global surveillance of physical activity
Authors: Mark S Tremblay
Journal: The Lancet Child & Adolescent Health (2019)

The changing world is changing people, with movement being one of the clearest indicators of this change. The electronic revolution has fundamentally transformed people's movement patterns by changing where and how they live, learn, work, play, and travel, progressively isolating them indoors (eg, houses, schools, workplaces, and vehicles), most often in chairs.1Kleinert S Horton R Urban design: an important future force for health and wellbeing.Lancet. 2016; 388: 2848-2850Summary Full Text Full Text PDF PubMed Scopus (27) Google Scholar People sleep less, sit more, walk less frequently, drive more regularly, and do less physical activity than they used to.2Guthold R Stevens GA Riley LM Bull FC Global trends in insufficient physical activity among adolescents: a pooled analysis of 298 population-based surveys with 1·6 million participants.Lancet Child Adolesc Health. 2019; (published online Nov 21)https://doi.org/10.1016/S2352-4642(19)30323-2Scopus (1073) Google Scholar, 3Tremblay MS Carson V Chaput JP et al.Canadian 24-hour movement guidelines for children and youth: an integration of physical activity, sedentary behaviour, and sleep.Appl Physiol Nutr Metab. 2016; 41: S311-S327Crossref PubMed Scopus (860) Google Scholar, 4Aubert S Barnes JD Abdeta C et al.Global Matrix 3·0 physical activity report card grades for children and youth: results and analysis from 49 countries.J Phys Act Health. 2018; 15: S251-S273Crossref PubMed Scopus (429) Google Scholar They are increasingly moving from one country to another, from rural to urban areas, from outdoors to indoors, from standing to sitting, from walking to driving, and from active play to digital play and, at a macroscopic level, countries are moving through epidemiological and economic transitions at varying rates. These changes in the human exposome fundamentally affect our movement behaviours, patterns, and contexts and could have profound effects on human health. These effects and how they vary spatially, temporally, or culturally are important, particularly since physical inactivity is the fourth leading risk factor for premature death worldwide, but remain poorly understood.5WHOGlobal health risks global health risks: MORTALITY and burden of disease attributable to selected major risks. World Health Organization, Geneva2009Google Scholar In their study published in The Lancet Child & Adolescent Health, Regina Guthold and colleagues2Guthold R Stevens GA Riley LM Bull FC Global trends in insufficient physical activity among adolescents: a pooled analysis of 298 population-based surveys with 1·6 million participants.Lancet Child Adolesc Health. 2019; (published online Nov 21)https://doi.org/10.1016/S2352-4642(19)30323-2Scopus (1073) Google Scholar make a valiant effort to consolidate and present regional and global estimates of the prevalence of insufficient physical activity among adolescents as well as global, regional, and national trends from 2001 to 2016. Using pooled data from 298 school-based surveys from 146 countries, territories, and areas, including 1·6 million students aged 11–17 years, they show that 81·0% (95% uncertainty interval 77·8–87·7) of adolescents are insufficiently physically active, with noticeably fewer insufficiently active boys (77·6% [76·1–80·4]) than girls (84·7% [83·0–88·2]). Furthermore, a significant temporal decrease between 2001 and 2016 was observed for boys whereas there was no change for girls, resulting in a widening of an already important sex difference. Socioeconomic patterns and trends at the country and regional levels were not consistent or clear, although the prevalence of insufficient physical activity was higher in low-income countries (84·9% [82·6–88·2]) than in high-income countries (79·3% [77·2–87·5]), somewhat counter to intuition and other findings.4Aubert S Barnes JD Abdeta C et al.Global Matrix 3·0 physical activity report card grades for children and youth: results and analysis from 49 countries.J Phys Act Health. 2018; 15: S251-S273Crossref PubMed Scopus (429) Google Scholar These results are arguably the best available estimates of global, regional, and temporal trends in adolescent physical activity levels, showing that the majority of adolescents do not meet current physical activity guidelines and that more boys than girls are active. Worldwide physical activity surveillance of adolescents is complex, susceptible to temporal and spatial drifts, and affected by many factors intervening at different times and with different intensities within and across countries. It is unknown whether brief, standardised questions about physical activity addressed to adolescents are equally valid across settings and countries and between sexes or whether the questions are interpreted in an equivalent way by each adolescent. Differences in these aspects might have affected Guthold and colleagues' findings by introducing measurement biases (due to country-specific or cultural-specific variability) or sex biases. Guthold and colleagues used available time trend data as well as possible, but the data are tenuous for reasons identified by the authors themselves (eg, differences in the number of countries, composition of countries, age ranges, sex balance, and questions or criteria for meeting guidelines across time). Some of the findings in Guthold and colleagues' Article2Guthold R Stevens GA Riley LM Bull FC Global trends in insufficient physical activity among adolescents: a pooled analysis of 298 population-based surveys with 1·6 million participants.Lancet Child Adolesc Health. 2019; (published online Nov 21)https://doi.org/10.1016/S2352-4642(19)30323-2Scopus (1073) Google Scholar do not support the Active Healthy Kids Global Alliance Global Matrix findings,4Aubert S Barnes JD Abdeta C et al.Global Matrix 3·0 physical activity report card grades for children and youth: results and analysis from 49 countries.J Phys Act Health. 2018; 15: S251-S273Crossref PubMed Scopus (429) Google Scholar which were based on a different surveillance synthesis approach and indicate that children and adolescents in low-income countries are more physically active than are those in high-income countries. This discord raises the question of whether either study, and if so which, is correct. Despite unequivocal evidence of health benefits of physical activity and of the extraordinary population attributable risk associated with insufficient physical activity, global surveillance of physical activity has been superficial, irregular, incomplete, and fraught with limitations. Monitoring progress toward the global target of a 15% relative reduction in insufficient physical activity6WHOGlobal action plan on physical activity 2018–2030. World Health Organization, Geneva2019Google Scholar needs reliable estimates to be derived in the future, which relies on the global deployment of routine, robust, and rigorous surveillance methods. In addition to the inadequate surveillance of global physical activity among adolescents (as well as children and adults), the importance of movement behaviours across the whole day is poorly recognised at a global level, as reflected in new 24-h movement guidelines.3Tremblay MS Carson V Chaput JP et al.Canadian 24-hour movement guidelines for children and youth: an integration of physical activity, sedentary behaviour, and sleep.Appl Physiol Nutr Metab. 2016; 41: S311-S327Crossref PubMed Scopus (860) Google Scholar, 7WHOWHO guidelines on physical activity, sedentary behaviour and sleep for children under 5 years of age. World Health Organization, Geneva2019Google Scholar Any surveillance reform should embrace this new paradigm and incorporate valid and reliable measures of physical activity (light, moderate, and vigorous), sedentary behaviours, digital media use, and sleep.3Tremblay MS Carson V Chaput JP et al.Canadian 24-hour movement guidelines for children and youth: an integration of physical activity, sedentary behaviour, and sleep.Appl Physiol Nutr Metab. 2016; 41: S311-S327Crossref PubMed Scopus (860) Google Scholar, 7WHOWHO guidelines on physical activity, sedentary behaviour and sleep for children under 5 years of age. World Health Organization, Geneva2019Google Scholar The field of movement behaviour epidemiology is in its infancy but must grow quickly. Transitions and evolutions (eg, across strata of human development, geospatial shifts, community design, automation, mechanisation, and digitisation) transform people's movement behaviours, often in harmful ways. These fundamental and pervasive changes threaten progress towards the UN Sustainable Development Goals,8UNSustainable Development Goals: 17 goals to transform our world.http://www.un.org/sustainabledevelopment/sustainable-development-goals/Date: 2016Date accessed: October 14, 2019Google Scholar as outlined in the Bangkok Declaration on physical activity for global health and sustainable development9International Congress on Physical Activity and Public HealthThe Bangkok declaration on physical activity for global health and sustainable development.https://static1.squarespace.com/static/559a3ff1e4b0b0193b9d9862/t/5843cdfbe3df28eae5f43c10/1480838663699/BKK_Declaration+FINAL+Dec2.pdfDate: 2016Date accessed: October 14, 2019Google Scholar and WHO's global action plan on physical activity.6WHOGlobal action plan on physical activity 2018–2030. World Health Organization, Geneva2019Google Scholar Too much is at stake not to carefully measure physical activity and monitor progress going forward. I declare no competing interests. Global trends in insufficient physical activity among adolescents: a pooled analysis of 298 population-based surveys with 1·6 million participantsThe majority of adolescents do not meet current physical activity guidelines. Urgent scaling up of implementation of known effective policies and programmes is needed to increase activity in adolescents. Investment and leadership at all levels to intervene on the multiple causes and inequities that might perpetuate the low participation in physical activity and sex differences, as well as engagement of youth themselves, will be vital to strengthen the opportunities for physical activity in all communities. Full-Text PDF Open Access