The Lancet Child & Adolescent Health: Majorit
- Globally, in 2016, 81% of 11 to 17-year-olds did not meet WHO recommendations for one hour of moderate to vigorous physical activity each day.
- Girls were less active than boys and this gap widened between 2001 and 2016, with rates of physical inactivity remaining similar for girls, while they improved slightly for boys.
- In 2016, in 27 countries, 90% or more of girls were not achieving sufficient activity levels, while this was the case in only two countries for boys.
- Boys in the Philippines and girls in South Korea were the most inactive, while Bangladesh had the lowest rates of physical inactivity for both boys and girls.
The world’s first-ever trends in insufficient physical activity among adolescents show that urgent action is needed to increase physical activity levels in girls and boys aged 11 to 17. The study, published in The Lancet Child and Adolescent Health journal and produced by researchers at the World Health Organization (WHO), finds that more than 80% of schoolchildren worldwide did not meet current recommendations of at least one hour of physical activity per day – including 85% girls and 78% boys.
The study – which is based on data reported by 1.6 million students aged 11 to 17 – finds that in the 146 countries studied between 2001 and 2016, girls were less active than boys in all countries except four (Tonga, Samoa, Afghanistan and Zambia).
The difference in the proportion of boys and girls responding to recommendations was more than 10 percentage points in almost one in three countries in 2016 (29%, 43 out of 146 countries), with the largest differences observed in the United States. United of America and Ireland (over 15 percentage points). Most of the countries in the study (73%, 107 out of 146) saw this gender gap widen between 2001-2016.
Youth health compromised by insufficient physical activity
The authors claim that insufficient physical activity levels in adolescents continue to be extremely high, compromising their current and future health. “Urgent political action to increase physical activity is needed now, especially to promote and maintain girls’ participation in physical activity,” says study author Dr Regina Guthold, WHO. 
The health benefits of a physically active lifestyle during adolescence include improved cardiorespiratory and muscle fitness, bone and cardiometabolic health, and positive effects on weight. It is also increasingly clear that physical activity has a positive impact on cognitive development and socialization. Current evidence suggests that many of these benefits carry over into adulthood.
To achieve these benefits, the WHO recommends that adolescents engage in moderate or vigorous physical activity for an hour or more each day. .
The authors estimated how many children aged 11 to 17 do not meet this recommendation by analyzing data collected through school-based surveys of physical activity levels. The assessment included all types of physical activity, such as time spent in active play, recreation and sports, active household chores, walking and cycling or other types of active transportation, physical education and planned exercise.
To improve physical activity levels in adolescents, the study recommends that: – There is an urgent need to expand effective policies and programs known to increase physical activity in adolescents; – Multisectoral action is needed to offer young people opportunities to be active, involving education, town planning, road safety and others; The highest levels of society, including national, municipal and local leaders, should promote the importance of physical activity for the health and well-being of all, including adolescents.
“The study emphasizes that young people have the right to play and should have the opportunity to realize their right to physical and mental health and well-being,” said co-author Dr Fiona Bull, WHO. “Strong political will and action can remedy the fact that four in five adolescents do not enjoy the pleasure and social, physical and mental benefits of regular physical activity. Policy makers and stakeholders must be encouraged to act now for the health of this and future young generations. ” 
Trends in physical activity show slight improvement for boys, none for girls
The new study estimated for the first time the evolution of trends between 2001 and 2016, applying trends from 73 countries that repeated surveys during this period to all 146 countries.
Overall, the prevalence of insufficient physical activity decreased slightly among boys between 2001 and 2016 (from 80% to 78%), but there was no change over time among girls (remaining around 85%).
The countries with the largest declines in the number of underactive boys were Bangladesh (73% to 63%), Singapore (78% to 70%), Thailand (78% to 70%), Benin (79% to 71%), Ireland (71% to 64%) and the United States (71% to 64%). However, among girls, the changes were small, ranging from a decrease of 2 percentage points in Singapore (85% to 83%) to an increase of 1 percentage point in Afghanistan (87% to 88%).
The authors note that if these trends continue, the global target of a 15% relative reduction in insufficient physical activity – which would lead to a global prevalence of less than 70% by 2030 – will not be met. . This target was endorsed by all countries at the World Health Assembly in 2018.
In 2016, the Philippines was the country with the highest prevalence of insufficient activity among boys (93%), while South Korea had the highest levels among girls (97%) and both sexes combined. (94%). Bangladesh was the country with the lowest prevalence of insufficient physical activity among boys, girls and both sexes combined (63%, 69% and 66%, respectively).
Some of the lowest levels of insufficient activity in boys have been found in Bangladesh, India, and the United States. The authors note that the lower levels of insufficient physical activity in Bangladesh and India (where 63% and 72% of boys were insufficiently active in 2016, respectively) can be explained by the high focus on national sports like cricket. However, the US rates (64%) can be determined by good physical education in schools, ubiquitous media coverage of the sport, and good availability of sports clubs (such as ice hockey, American football, basketball or baseball).
For girls, the lowest levels of insufficient activity were observed in Bangladesh and India, and are potentially explained by societal factors, such as increased household chores for girls.
Insufficient activity in adolescents is a major concern
“The tendency of girls to be less active than boys is worrying,” said study co-author Dr Leanne Riley, WHO. “More opportunities to meet the needs and interests of girls are needed to attract and maintain their participation in physical activity through adolescence and into adulthood. ” 
To increase the physical activity of young people, governments must identify and address the many causes and inequalities – social, economic, cultural, technological and environmental – that can perpetuate the differences between boys and girls, the authors said.
“Countries need to develop or update their policies and allocate the necessary resources to increase physical activity,” says co-author Dr Fiona Bull. “Policies should increase all forms of physical activity, including through physical education that develops physical literacy, more opportunities for sports, active play and recreation – as well as providing safe environments for young people to walk and cycle independently. Comprehensive action requires engagement with multiple sectors and stakeholders, including schools, families, sports and recreation providers, city planners, and city and community leaders. ” 
The authors note some limitations, including the fact that the study only included information from school-going adolescents, due to the lack of data for out-of-school adolescents. Adolescents in school may differ from others of the same age, as adolescents in school may be more likely to come from advantaged backgrounds that may be more focused on achieving success in other academic disciplines, rather than physical education and sport. In addition, while the study covered 81% of the adolescent population in school, this coverage varied by country income, ranging from 36% in low-income countries to 86% in high-income countries.
The study used only self-reported data, which may be subject to bias. Data from portable devices was not used as it could not be compared to self-reported survey data.
Writing in a related commentary, Dr Mark Tremblay, Children’s Hospital of Eastern Ontario Research Institute, Canada, states: “The changing world is changing people, with movement being one of the most important indicators. more clear about this change. The electronic revolution has fundamentally transformed the movement of people. changing where and how they live, learn, work, play and travel, gradually isolating them indoors (eg, homes, schools, workplaces and vehicles), most often on chairs. , drive more regularly and do less physical activity than before. They are moving more and more from country to country, from rural to urban areas, outdoors to indoors, from standing to sitting, from walking to driving and playing. active in digital play and, at a macroscopic level, countries are going through epidemiological and economic transitions at varying rates. These changes in the human exposome fundamentally affect our own movement behavior, patterns and contexts and could have profound effects on human health. These effects and their spatial, temporal or cultural variation are important, especially since physical inactivity is the fourth risk factor for premature death in the world, but remain poorly understood. ”
Peer review / Observation and modeling / People
NOTES TO EDITORS
This study was funded by the World Health Organization. It was conducted by researchers from WHO, Imperial College London and the University of Western Australia.
The labels were added to this press release as part of a project led by the Academy of Medical Sciences to improve the communication of evidence. For more information, please see: http://www.sciencemediacentre.org/wp-content/uploads/2018/01/AMS-press-release-labelling-system-GUIDANCE.pdf If you have any questions or comments, please contact The Lancet press office [email protected]
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 For more information, please see: https://www.who.int/dietphysicalactivity/factsheet_recommendations/en/
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