World Health Organisation and United States guidelines say adolescents should do at least an hour’s moderate-to-vigorous physical activity each day. But a new global study shows eight out of 10 fail to meet that standard – and there is a widening gender gap. Professor Yvonne Kelly and Fran Abrams outline new research revealing worrying trends which demonstrate the need for political and social choices that will help young people enjoy the social, physical and mental benefits of being active.
Physical activity has many health benefits for young people – and globally, four in every five adolescents do not benefit from regular physical activity.
In 2018, the WHO launched a global action plan called More Active People for a Healthier World. It aimed to reduce the proportion of people doing insufficient physical activity by 15 per cent by 2030 among both adolescents and adults.
Now in a major new study WHO researchers have analysed information on 1.6 million school students aged 11-17 in 146 countries. They found some positive trends but argued much still needed to be done to encourage young people to exercise more.
There was a small reduction over 15 years in the proportion of boys not doing enough, though this still fell well short of the WHO’s target. But the proportion of girls meeting the target remained static and this led to a widening gender gap.
The authors of a separate investigation using the Millennium Cohort Study (MCS) suggest the main reason for young people not exercising or sleeping enough is the amount of time they spend using screens. This is a hotly contested area, intuitively, ‘too much screen time’ and ‘too little exercise’ might appear to sit side by side. However, in this kind of study, it is not possible to infer that one causes the other.
The WHO study showed the majority of adolescents did not meet physical activity guidelines, putting their current and future health at risk. Although there were small reductions in insufficient activity among boys, the prevalence of insufficient physical activity in girls had remained unchanged since 2001.
The dataset used in the WHO study was huge – the young people studied had provided information for at least three years and the analysis covered four World Bank income groups, nine regions, and the globe as a whole for the years 2001–16. Saying that, although the research data covered more than 80 per cent of the global population, it still didn’t cover every county and region. And the estimates for low-income countries need to be treated with caution as the coverage there was much lower – only 36 per cent.
The overall analysis showed that more than eight out of 10 school-going adolescents aged 11–17 did not meet the recommendations for daily physical activity. The small improvements in boys’ activity levels, combined with the static position in girls’ activity, suggested a target of more than 30 per cent of adolescents meeting the recommended level by 2030 will not be met.
Globally, across all income groups and regions and in nearly all the countries analysed, girls were less active than boys.
And perhaps surprisingly, the research did not find that the problem was worse in higher-income countries. However, this was not the case for girls, for whom there was no clear pattern in relation to country income.
Differences in activity levels
In addition to variations related to gender and affluence, there were also differences in activity levels between different parts of the world. The boys least likely to meet activity targets were in the high-income Asia Pacific region, but the second-least likely were in lower-income Sub-Saharan Africa and particularly in Sudan and Zambia.
The boys most likely to meet the targets were found in high-income western and south Asian countries with large populations such as the USA, Bangladesh, and India.
These variations might be driven by specific characteristics of particular countries – for example, as the research looked at school children the picture might be skewed in countries where disadvantaged children often do not attend school, or in places where the tradition of school or community sport is strong.
For girls, the largest proportions failing to meet the targets were in Asia Pacific and particularly in South Korea- though in some of those countries girls’ participation in education is low and that might have affected the study’s sample.
The recent MCS study by academics from Loughborough University and University College London used data from 3899 adolescents. This study, in which young people were fitted with activity monitors, found that while nine out of 10 were getting the recommended amount of sleep, just four in ten met exercise targets and a quarter were keeping to the recommended screen time. These figures were higher than those in the WHO study, which could be explained by the different methods used to measure activity and which show just how important it is to consider HOW activity is measured.
The study looked at some correlates of physical activity and showed that adolescent girls who had depressive symptoms were less likely to meet all three of these recommendations (8-10 hours of sleep, no more than two hours of screen time and at least an hour a day of physical activity), while those from better-off backgrounds were more likely to meet them. Among boys, those who were obese and those who had depressive symptoms were less likely to meet the recommendations. However, it is not possible to rule out the potential for cyclical associations to be at play here as low levels of physical activity could lead to depressed mood and to weight gain.
What can be done?
- More research is needed to understand the causes of non-participation in exercise – social, economic, cultural, environmental and technological.
- Policy change should be prioritised and should encourage all forms of physical education – sport, active play, and recreation as well as safe walking and cycling.
- Social marketing campaigns such as the National Lottery funded #thisgirlcan campaign combined with community-based interventions could be starting points to increase physical activity levels in girls, particularly in countries with wide gender differences. This approach has been identified as cost-effective.
- Schools, families, sport and recreation providers, urban planners, and city and community leaders all need to become involved.
That four in every five adolescents do not experience the enjoyment and social, physical, and mental health benefits of regular physical activity is not a chance thing – it is the consequence of political choices.
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. Urgent action is needed, particularly through targeted interventions to promote and retain girls’ participation in physical activity. Policymakers and stakeholders should be encouraged to act now for the health of this young generation and of future ones.
Yvonne Kelly is Professor of Lifecourse Epidemiology and Director of the ESRC International Centre for Lifecourse Studies at UCL. She is editor of the Child of our Time blog.
Fran Abrams is CEO of the Education Media Centre and freelance journalist who writes for the Child of our Time blog.
Global trends in insufficient physical activity among adolescents: a pooled analysis of 298 population-based surveys with 1·6 million participants, by Regina Guthold, Leanne Riley, Fiona Bull and Gretchen Stevens, is published in The Lancet Child and Adolescent Health.
Regina Guthold, Leanne Riley and Fiona Bull are based at the Department for Prevention of Noncommunicable Diseases, WHO, Geneva, Switzerland and Gretchen Stevens is at the Department for Information, Evidence and Research, WHO, Geneva, Switzerland. Fiona Bull is also affiliated with the Department of Sport and Exercise Science, University of Western Australia, Perth.
Prevalence and Correlates of Meeting Sleep, Screen-Time, and Physical Activity Guidelines Among Adolescents in the United Kingdom, by Natalie Pearson, Lauren B Sherar and Mark Hamer, is published in JAMA Paediatrics:
Natalie Pearson and Lauren Sherar are at the School of Sport, Exercise & Health Sciences, Loughborough University, United Kingdom, and Mark Hamer is at the Institute of Sport Exercise & Health, Division of Surgery & Interventional Science, Faculty of Medical Sciences, University College London, United Kingdom.