We included 298 school-based surveys from 146 countries, territories, and areas (appendix 3 pp 2–9), representing 1·6 million students aged 11–17 years (81·3% of the global population of adolescents of this age). Data availability rose with country income, from 8 (26%) of 31 low-income countries with data available to 56 (75%) of 75 high-income countries with data available. Regional data availability ranged from 16 (30%) of 53 countries with data in Sub-Saharan Africa to 6 (100%) of 6 countries in south Asia (table 1).
Table 1Distribution of data sources across income groups and regions
73 (50%) of 146 countries, territories, and areas with data (ie, 31·6% of all 231 countries globally) had trend data, defined as data from at least 2 different years between 2001 and 2016. Trend-data availability increased with country income and ranged across regions from no countries with trend data in south Asia to 14 (70%) of 20 countries in central and eastern Europe (table 1). Data availability was relatively evenly distributed across time, with 91 (31%) of 298 surveys from 2006 or earlier, 104 (35%) from 2007–2011, and 103 (35%) from 2012 or later (appendix 3 pp 2–9).
More than four in five school-going adolescents aged 11–17 years were insufficiently physically active in 2016 (81·0% [95% UI 77·8–87·7]). Between 2001 and 2016, prevalence decreased by 2·5 percentage points (significant change) for boys (from 80·1% [78·3–81·6] to 77·6% [76·1–80·4]), whereas there was no significant change for girls (from 85·1% [83·1–88·0] to 84·7% [83·0–88·2]; figure 1), leading to a significant global difference of 7·1 percentage points in insufficient activity between sexes in 2016. If these trends continue, the global target of a 15% relative reduction in insufficient physical activity will not be met by 2030.
Figure 1Prevalence of insufficient physical activity among school-going adolescents aged 11–17 years, globally and by World Bank income group, 2001 and 2016
There was no clear pattern in prevalence according to country income group: insufficient physical activity was 84·9% (95% UI 82·6–88·2) in low-income countries, 79·3% (77·2–87·5) in lower–middle-income countries, 83·9% (79·5–89·2) in upper–middle-income countries, and 79·4% (74·0–86·2) in high-income countries in 2016. Although prevalence of insufficient activity showed small but significant decreases for boys of all income groups between 2001 and 2016 (except for lower–middle income), there were no decreases in any income group for girls, leading to widening differences in insufficient activity levels between sexes over time. In 2016, differences in insufficient activity between sexes ranged from 4·7 percentage points in lower–middle-income countries to 11·8 percentage points in high-income countries (figure 1).
High-income Asia Pacific was the region with the highest prevalence of insufficient physical activity in 2016 for both boys (89·0% [95% UI 62·8–92·2]) and girls (95·6% [73·7–97·9]). Sub-Saharan Africa was the region with the second highest prevalence of insufficient activity among boys (83·9% [82·3–85·0]), whereas for girls the region with the second highest prevalence was central Asia, Middle East, and north Africa (89·9% [88·6–90·9]). By contrast, high-income western countries (72·1% [71·1–73·6]) and south Asia (73·1 [69·3–86·9]) showed lowest prevalence in boys, and south Asia in girls (77·5% [72·8–89·3]; table 2).
Table 2Estimated prevalence of insufficient physical activity among school-going adolescents aged 11–17 years by sex and overall, 2001 and 2016
Across all regions, girls were less active than boys, with significant differences between sexes in seven of the nine regions. Insufficient physical activity did not change for girls or both sexes combined in any region; however, male prevalence showed small but significant decreases in five of the nine regions (high-income western countries, Latin America and the Caribbean, Oceania, south Asia, and sub-Saharan Africa; figure 2). As a result, with the exception of high-income Asia Pacific, differences between sexes were widening in all regions, resulting in a range of a 4·3 percentage-point difference in Oceania to a 12·5 percentage-point difference in high-income western countries in 2016 (figure 2).
Figure 2Prevalence of insufficient physical activity among school-going adolescents aged 11–17 years, by sex and region, 2001 and 2016
In 2016, prevalence of insufficient physical activity was more than 80% in 71 (49%) of 146 countries analysed for boys versus 141 (97%) for girls, more than 85% in 20 (14%) countries for boys versus 112 (77%) countries for girls, and more than 90% in two (1%) countries for boys versus 27 (18%) countries for girls (table 2; Figure 3, Figure 4).
Figure 3Prevalence of insufficient physical activity among school-going boys aged 11–17 years, 2016
Figure 4Prevalence of insufficient physical activity among school-going girls aged 11–17 years, 2016
Philippines was the country with the highest prevalence of insufficient activity among boys (92·8 [91·2–94·1]), whereas South Korea showed highest levels among girls (97·2 [95·2–98·4]) and both sexes combined (94·2 [90·3–96·6]). Bangladesh was the country with the lowest prevalence of insufficient physical activity among boys (63·2 [55·0–70·6]), girls (69·2 [61·3–76·1]), and both sexes combined (66·1 [58·1–73·3]; table 2).
Girls were less active than boys in all but four (3%) countries (Tonga, Samoa, Afghanistan, and Zambia), in 2016. In 43 (29%) countries, the difference between sexes was greater than 10 percentage points and in the USA and Ireland it was greater than 15 percentage points (appendix 3 p 18).
Among boys, in 6 (4%) of the 146 countries in our analysis, prevalence of insufficient activity decreased by more than 5 percentage points since 2001 (Bangladesh, Singapore, Thailand, Benin, Ireland, and the USA), whereas in Italy and Australia it increased by more than 3 percentage points. Among girls, changes in insufficient activity prevalence over time were small, ranging from a 1·7 percentage-point decrease in insufficient activity in Singapore to a 0·9 percentage-point increase in Afghanistan. Differences in prevalence between sexes widened from 2001 to 2016 in most countries analysed (107 [73%] of 146; table 2).
Discussion
Our analysis shows that globally, in 2016, more than 80% of school-going adolescents aged 11–17 years did not meet current recommendations for daily physical activity, compromising their current and future health.
WHO Global Recommendations on Physical Activity for Health.
Although the prevalence of insufficient physical activity has slightly decreased in boys since 2001, there was no change over time in girls, and if these trends continue, the global target of a 15% relative reduction in insufficient physical activity—which would lead, if met, to a global prevalence of less than 70% by 2030—will not be achieved.
We found that globally, across income groups and regions and in nearly all countries analysed, girls were less active than boys and the prevalence of female insufficient activity, in particular, has not improved since 2001. Differences in prevalence of insufficient physical activity between boys and girls and widening gaps over time were particularly apparent in some high-income countries, such as Singapore, the USA, and Ireland, all showing an absolute difference in prevalence between boys and girls of more than 13 percentage points in 2016 (an increase in sex difference of more than 5 percentage points relative to 2001). These differences between sexes
Trends in physical activity, sedentary behavior, diet, and BMI among US adolescents, 2001-2009.
have been confirmed by several articles describing national data from these countries, as well as by objective, device-based data from other countries such as Canada with estimates similar to ours.
Comparison of self-reported and accelerometer-measured physical activity among Canadian youth.
A previous meta-analysis reported that changing physical activity behaviour, particularly in adolescent girls, is challenging; however, small effects of some interventions are reported, specifically those that were underpinned by theory and based on multicomponent strategies.
The effectiveness of school-based physical activity interventions for adolescent girls: A systematic review and meta-analysis.
Furthermore, there are examples of national campaigns that have effectively addressed specifically the gender gap (eg, This Girl Can campaign in the UK).
Although the target population for this campaign is adult women, the visibility and creation of more active female role models can positively influence girls’ decisions and participation. Social marketing campaigns combined with community-based interventions should be starting points to increase physical activity levels in girls, particularly in countries with wide differences between sexes. This approach has been identified as cost-effective,
Worldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1·9 million participants.
we did not find that prevalence of insufficient activity in school-going adolescents increased with country income. On the contrary, male adolescents from high-income countries showed the lowest prevalence of insufficient activity in our analysis, whereas those from low-income countries showed the highest prevalence. However, this was not the case for girls, for whom we did not find any pattern with regards to country income. Previous research on the effect of socioeconomic status on physical activity participation among adolescents indicates that adolescents with higher socio-economic status tended to be more active than those with lower socioeconomic status, perhaps because of more opportunities at school and in the community to be active for adolescent boys, whereas there might be fewer opportunities meeting the needs and interests of adolescent girls. However, findings on this social patterning across studies are not uniform,
Effects of socioeconomic status on the physical activity in adolescents: a systematic review of the evidence.
and more research is needed to improve the understanding of this relationship.
We found the highest levels of insufficient activity in boys in high-income Asia Pacific. Sub-Saharan Africa was the region with the second highest prevalence of insufficient activity among boys, with particularly high prevalence values in Sudan and Zambia. It must be noted that we only included school-going adolescents in our sample, which might represent not only a small proportion of this age group in these settings, but perhaps also a population with special characteristics. For example, these adolescents might be more likely to come from more advantaged households, that might be more focused on high achievement in other academic disciplines, rather than physical education, sports, and active recreation. The low priority given to physical activity within the context of some schools and parental attitudes is a frequently cited barrier as it reduces the support and opportunities available to adolescents.
Physical activity during school recess: a systematic review.
Some of the lowest levels of insufficient activity in boys were found in high-income western countries and south Asia, driven by countries with large populations like the USA, Bangladesh, and India. The quite low prevalence of insufficient activity in boys in Bangladesh and India might be explained by the strong focus on national sports, such as cricket, which is frequently played unstructured in local communities. In the USA, these data might be explained by better physical education in schools, the pervasive media coverage of sports, and a strong presence of sports clubs providing many opportunities to play in structured, organised sport (such as ice hockey, American football, basketball, or baseball), often rather male-dominated activities.
For adolescent females, the high-income Asia Pacific region showed the highest levels of insufficient activity, largely driven by South Korea. The region with the lowest levels of insufficient activity in 2016 in girls was south Asia, which includes Bangladesh and India. These two countries reported the lowest prevalence in female insufficient activity in our study, potentially explained by societal factors, such as girls being required to support activity and domestic chores around the home.
Our results need to be interpreted in light of several limitations. First, we only included school-going adolescents in our analysis, and our results are therefore not representative of the entire adolescent population of each country. In some countries and regions, out-of-school adolescents represent a large population
UN EducationalScientific and Cultural Organization Institute for Statistics One in five children, adolescents and youth is out of school.
with potentially different behaviours as compared with school-going adolescents. Including out-of-school adolescents in our analysis would probably have influenced our findings but was not possible because of lack of data in this largely understudied population.
The Global Action for Measurement of Adolescent health (GAMA) initiative—rethinking adolescent metrics.
We call for this gap in surveillance of physical activity to be urgently addressed to enable countries to respond and meet the call for reporting of disaggregated health statistics.
Defining adolescence: priorities from a global health perspective.
Second, the surveys included in our analysis covered different years of the adolescent age range, which we aggregated into a single estimate for adolescents aged 11–17 years. Most importantly, the HBSC, done in many European and North American countries, includes adolescents aged 11 years, 13 years, and 15 years, whereas the GSHS focused on adolescents aged 13–15 years until 2012, and then expanded to adolescents aged 13–17 years. Our aggregation of all ages might have led to increased estimates of insufficient activity in countries where older age groups were included, since some national reports
Timing of the decline in physical activity in childhood and adolescence: Gateshead Millennium Cohort Study.
found declines in physical activity occurred earlier (around the age of 7 years), and less so during adolescence. A recent review by Kemp and colleagues on longitudinal changes in domains of physical activity during childhood and adolescence
Longitudinal changes in domains of physical activity during childhood and adolescence: A systematic review.
showed no change in transport or in organised sport participation during adolescence, and concluded that most changes in physical activity behaviour are likely to happen before adolescence, while mentioning that changes in non-organised physical activity have been studied less. Notably, this review reported data by specific domains of physical activity, such as activity for transport, in school, in sport clubs, or unstructured active play, which was not possible in our global dataset in which we could only report on overall physical activity, because of non-comparable national survey data on other domains. This inconsistency in monitoring is also seen in many other areas of adolescent health measurement and calls for development of more standardised and harmonised tools for collection and reporting—an area that the Global Action for Measurement of Adolescent health is aiming to address.
An Updated Systematic Review of Childhood Physical Activity Questionnaires.
including potential social desirability bias and cross-cultural, age, or sex differences in reporting. For instance, although examples of setting-specific activities were usually provided in the question text of surveys we included, active transportation and domestic chores might not always be included in reporting, potentially leading to biased estimates. Another flaw includes the sometimes-limited validity and reliability of survey instruments. Although questionnaires used in studies that were included in our analysis were tested for validity and reliability in different settings
Test-retest reliability of selected items of Health Behaviour in School-aged Children (HBSC) survey questionnaire in Beijing, China.
Using device-based, objective data for estimation of regional and global estimates of insufficient physical activity is currently not possible, since the availability of nationally representative, device-based measured physical activity data among adolescents is limited to a few, mainly high-income countries.
Utilization and harmonization of adult accelerometry data: review and expert consensus.
there are no global standard protocols for analysing and reporting of device-based measurements, and different data cleaning methods and cut-points are applied in different studies, leading to non-comparability of results.
What proportion of youth are physically active? Measurement issues, levels and recent time trends.
In a recent study, Migueles and colleagues concluded that it is currently not possible to know the prevalence of meeting physical activity guidelines based on accelerometer data.
An assessment of self-reported physical activity instruments in young people for population surveillance: project ALPHA.
such as those used in surveys included in our analysis, are the only option for this type of large global and regional analyses. The development of standardised methods and analysis protocols for device-based assessment of physical activity, such as continuing efforts by partners involved in the International Children’s Accelerometry Database,
Epidemiology Unit Medical Research Council International Children’s Accelerometry Database (ICAD).
remains an urgent priority for this field.
Finally, similar to all large global and regional analyses, data were not available for every country and year, and availability varied across countries and regions. Although available data covered more than 80% of the global population, the population of low-income countries was only covered by 36%. Trend-data availability was also skewed towards high-income countries, and our estimates for low income countries therefore need to be interpreted with caution.
In 2018, all countries committed to implementing the policy actions recommended in the GAPPA,
WHO Global action plan on physical activity 2018-2030: more active people for a healthier world.
and the data presented in this paper emphasise the urgent need for accelerating the speed and scale of national and subnational responses. WHO guidance
WHO ACTIVE: a technical package for increasing physical activity Geneva.
recommends that all countries develop or update national policy and implementation plans on physical activity and, most importantly, allocate the necessary political priority and resources to enable implementation, or their commitment to increase physical activity will not be achieved. Without exception, all countries should prioritise policy and programmes that target children and adolescents, especially girls.
Effectively addressing the high prevalence of insufficient activity will require identifying, understanding, and intervening on the causes and inequities—social, economic, cultural, technological, and environmental—that can perpetuate the low levels of participation and differences between sexes. Policy actions should aim to address increasing physical activity in all its forms, including physical education that develops foundational physical literacy, sport, active play, and recreation, as well as safe independent mobility (walking and cycling). Comprehensive action will require engagement and coordinated responses across multiple sectors and stakeholders including, but not limited to, schools, families, sport and recreation providers, urban planners, and city and community leaders. To support countries, global and regional guidance on effective approaches exist,
Public Health Agency of Canada A Common Vision for increasing physical activity and reducing sedentary living in Canada: Let’s Get Moving.
In summary, our analysis, based on 1·6 million school-going adolescents, is the first to estimate levels of insufficient physical activity across 146 countries and to assess global, regional, and country time trends in insufficient physical activity. Our data show that the majority of adolescents do not meet physical activity guidelines, putting their current and future health at risk. Although there appear to have been small reductions in insufficient activity among boys, prevalence of insufficient physical activity in girls has remained unchanged since 2001, leading to widening sex differences. Urgent action is needed now, particularly through targeted interventions to promote and retain girls’ participation in physical activity. Policy action aimed at increasing physical activity should be prioritised, and stronger government and stakeholder leadership is needed to support the scaling of responses across multiple sectors. Young people have the right to play and should be provided with the opportunities to realise their right to physical and mental health and wellbeing. That four in every five adolescents do not experience the enjoyment and social, physical, and mental health benefits of regular physical activity is not by chance, but a consequence of political choices and societal design. The contribution of policy actions that will increase physical activity will, at the same time, support achieving multiple Sustainable Development Goals. Policy makers and stakeholders should be encouraged to act now for the health of this and future young generations.
RG analysed the data and wrote the first draft of the manuscript. RG and GAS developed the methodological approach, with inputs from all other authors. RG and FCB interpreted the data and wrote the discussion. All authors conceived the study and revised and approved the final manuscript.
RG, LMR, and FCB are staff members at WHO. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the decisions, policy, or views of WHO. We declare no competing interests.
