Physical activity is an important correlate of health across the life course. This lecture will review the definition of physical activity in young people. Explore how physically active young people are. Understand where the patterns of physical established in adolescence persistent to adulthood or not. And consider some of the social and economic determinants of physical activity. But before we start, I'd like you to think about your own patterns and levels of physical activity last week. How much physical activity did you do? How much would you have liked to do, but didn't? And what got in the way? The World Health Organization defines physical activity as any bodily movement produced by skeletal muscles that requires energy expenditure. Including activities undertaken while working, playing, carrying out household chores, travelling, and engaging in recreational pursuits. There are major health risks of physical inactivity. With it being identified as the fourth leading risk factor for global mortality, causing an estimated 3.2 million deaths each year. As a risk factor in 6% of all deaths, physical inactivity is only outstripped by high blood pressure and tobacco use. It carries the same level of risk to mortality as high blood glucose. We know that physical inactivity is on the rise in many countries, adding to the burden of non-communicable diseases in adults. People who are insufficiently active have a 20 to 30% increased risk of death compared to people who engage in at least 30 minutes of moderate intensity physical activity on most days of the week. Now, the term physical activity should not be confused with exercise, which is a subcategory of physical activity that is planned, structured, repetitive, and aims to improve or maintain one or more components of physical fitness. The adolescents on the left can be seen to be engaging in exercise. While the cycling girls and swimming boys are simply being physically active. Now the World Health Organization recommends that children and adolescents spend 60 minutes each day participating in moderate to vigorous intensity physical activity. For adults, they recommend a 150 minutes of moderate intensity activity per week. At the introduction to this lecture when I asked you to reflect on how active you'd been last week, did you get this amount? If not, now might be a good time to go and get active, and come back and complete this later. Population surveys show that many young people are not meeting these guidelines. Although about 80% of our adolescents are estimated to spend at least 30 minuets a day being active, probably less than half are active at least 60 minutes a day. Interestingly, pride to adolescents, the amount of time that boys and girls spend being physically active is pretty similar. From adolescence however, the amount of time that both boys and girls engage in physical activity becomes reduced, but much more so for girls than boys. About two-thirds of adolescent boys and a quarter of adolescent girls report doing 20 minutes of sustained moderate to vigorous physical activity three times a week. Studies using self-report measures usually find more physical activity than those using objective measures although not necessarily in the direction you might expect. For example, one recent study showed that those most likely to overestimate their physical activity were slim. Because physical activity has important health benefits in youth, and many young people are not meeting established guidelines. Improving adolescent physical activity levels is an important public health challenge. There is burgeoning research interests in understanding the various correlates of physical activity and how we best promote physical activity. We know, for example, that there are significant individual differences around physical activity between young, one young person and another. And while we know about these individual differences, we also know how much socio-cultural, geographic and economic influences contribute to levels of physical activity. There is a reasonable level of continuity of physical activity in individuals across the life course. For example the Young Finns study from Finland explored individual continuities in a large cohort of children and adolescents who were recruited in 1980, and then followed every three years until 1992, then again in 2001. When they ranged in age form 24 to 39 years. Self-reported physical activity was measured at each wave and persistent physical activity was defined as a score in the most active third of the physical activity indicator in two or three consecutive waves of the longitudinal study. This study showed that individuals with persistent physical activity across the childhood and adolescent waves were also more likely to be physically active in adulthood. In other words, they showed that a high level of physical activity at ages 9 to 18, especially when continuous, significantly predicted a high level of adult physical activity. But beyond individual differences, what do we know about the wider influences on physical activity levels? What do you think might be influential in your community or in other communities, countries, and regions? Wider influences might include understanding the impact of attitudes, practices, and support for physical activity in the family. The extent to which young people are supported to be physically active at school, including transportation to and from school, as well as a wider set of attitudes towards physical activity within a community, especially around gender roles. We can appreciate some of these differences if we compare a country like Denmark, as I've shown on this side on the left, with that of Indonesia, which are the remaining sides. Denmark is a country with high rates of walking and bicycle commuting. Not only does Denmark have a history of cycling as a form of transportation for both males and females, but there is significant cycling infrastructure in terms of bicycle paths. The geography is also highly supportive as the country is flat and the climate is relatively conducive to cycling. In the capital, Copenhagen 36% of all citizens commute to work, school or university by bike. Denmark is a wealthy country, and the quality of footpaths and the extent of public transportation support walking rather than driving. However, none of this has happened by chance. Rather, it is the result of some very specific transportation policies that have had equally impressive benefits for health. On the other side of the world in Indonesia, the tropical climate is far less conducive to walking and cycling. The quality of foot paths is also highly variable as I personally photographed here when trying to go for a walk at a conference I attended in Palembang last year. When I had to concentrate pretty hard as you might imagine seeing this foot foot, foot path, not to break an ankle. There are no cycle paths. Short journeys are far more likely to be made by motor bike, than by walking or cycling. Public buses are a popular form of transport for long journeys, but as the country becomes wealthy growing numbers of cars are proving highly challenging to the road infrastructure. Which is effectively gridlocked much of the time, certainly in the major cities. There has been little investment in a rail network. We can see here the wider influence of cultural attitudes towards physical activity. Throughout the world there are highly gendered approaches to exercise. So for example, while these Afghani young women on the left are enjoying a basketball game. I doubt very much that there is strong support within the community for these young women to play notwithstanding the careful modifications to the sports dress consist with the community's social and religious expectations. And while cycling is a common form of transportation, in many parts of the world, it is more acceptable in the context of male roles within the family or at work, rather than for girls and women. I don't know if any of you have seen the Saudi Arabian film Wadjda, the first Saudi film to be directed by a woman, Haifaa al-Mansour. This delightful film centres on the ten year old Wadjda, whose passions to own and ride a bicycle is used as a metaphor for freedom and empowerment of women. It is made apparent that she is rapidly approaching the age at which she will be unable to continue to ride a bike. So how do we increase levels of physical activity? In 2013 WHO member states agreed to reduce physical inactivity by 10%. In the framework of the global action plan for the prevention and control of non-communicable diseases. At that time, policies and plans to address physical inactivity had been developed in about 80% of WHO member states. However, while international policy can be set, it is national and then local authorities that must adopt firstly, and then importantly, implement policies in a range of sectors to promote and facilitate physical activity. If you are the minister for health wishing to increase physical activity levels in young people in your country, what are the types of policies you would wish to introduce? I imagine that, as with the WHO policy, you might wish to introduce policies to increase physical activity, that set out to ensure that walking, cycling, and other forms of active transportation are accessible and safe for all. That labor and workplace policies encourage physical activity. That schools have safe spaces and facilities for students to spend their free time actively. That quality physical education supports young people to develop behavioural patterns that will keep them physically active throughout their lives. And that sports and recreation facilities provide opportunities for everyone to do sport. And if you are the minister for health, you would also need to think very hard about equity of access and gender. If you were truly to implement your policies for all. The results of programmatic interventions to increase physical activity are relatively unexciting. In this systematic review, the strongest evidence in adolescents was for school based interventions with multicomponent interventions that also involve families and the community. Much more research is required in this space. But in the meantime, I'm off for a walk. Maybe you should have one, too.
