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The benefits of a physically active childhood

Emma Croghan
RGN RSCN RSCPHN BSc(Hons) MPH MSc PhD (sub)
Director of Research and Training
Elc Consultancy Ltd
Chair West Mids Young People Tobacco Control Network
Editor British Journal of School Nursing

There is international and national concern about the increasing prevalence of obesity in children. The number of overweight and obese children in the UK has risen steadily over the past 20 years. Since 1990, obesity among UK children has increased rapidly. In 1990, 5% of all children were noted as above the 95th percentile for body mass index (BMI), and therefore classified as overweight, and 2% were above the 98th (and therefore classified as obese). Eleven percent of 6-year-olds and 17% of 15-year-olds were overweight or obese (above the 95th percentile) in 1996.(1) In 2002, 30% of all children aged between 2 and 15 were above the 95th percentile.(2)

Recommendations
The English Chief Medical Officer recommends that:
"Children and young people (aged 5 to 18 years) should achieve a total of at least 60 minutes of at least moderate-intensity physical activity each day. At least twice a week this should include activities to improve bone health, muscle strength and flexibility. This can be gained in one session, or through several shorter bouts of activity of 10 minutes or more."(3)
At present, 70% of English boys and 61% of girls aged between 2 and 15 are achieving the recommended amount of activity per week.(4) This means that over a third of children and young people are not getting enough quality activity to promote good health (see Figure 1).

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Activity types
There are, broadly, three categories of activity:

  • Cardiovascular activity: makes the heart beat faster and results in feeling mildly out of breath. This type of activity is good for improving and maintaining the efficiency of the functioning of the heart, lungs and circulatory system. Running, dancing and jumping are good examples of this type of activity.
  • Strength and resistance activity: increases overall metabolism, bone strength and muscle strength and mass. Squats, push-ups, jumping elastic bands as well as weight training are all examples of this type of activity.
  • Flexibility activity: improves and maintains joint range and motion. This includes yoga and stretching activities.

Benefits of physical activity
Children who are overweight tend to grow up into adults who are overweight, and children who are inactive are likely to continue this inactivity into adulthood.(6)
 They therefore have a higher risk of developing serious health problems in later life, including heart attack and stroke, type 2 diabetes, bowel cancer and high blood pressure. The risk of health problems increases the more overweight a person becomes.
Being overweight as a child can also cause psychological distress.(7) Teasing about their appearance affects children's confidence and self-esteem and can lead to isolation and depression.
Increasing physical activity in childhood could help reduce overweight and improve weight/height/development outcomes among children as well as providing other benefits. Physical activity has a range of benefits during childhood, including healthy growth and development, maintenance of energy balance and psychological wellbeing. It also has a direct link to preventing the later development of cardiovascular disease risk factors (such as obesity, raised blood pressure and adverse lipid profiles), through preventing excess weight gain during childhood, or promoting weight loss in overweight children.(8)
This increase in childhood obesity and reduction in childhood activity reflects a wider trend among the adult population in the UK and in other countries. Prevalence of obesity among adults in England has almost trebled in the last 20 years, but by 2020 the predicted prevalence of childhood obesity will be in excess of 50%.(9)
However, it is important to note that obesity in childhood differs from obesity in adults in definition and meaning. Children need food to grow and develop. Growth and development in childhood is only possible if energy intake exceeds energy output. During puberty alone, a child will double their weight and their height will increase by 20%. In early adolescence, a natural growth spurt signals the beginnings of puberty. It is therefore natural for adolescents to gain weight and for their bodies to change shape, but often they will feel dissatisfied because they do not perceive them as "ideal". On one hand, children hear that overweight and obesity among adolescence is increasingly prevalent, over one-fifth of all 13-16-year-olds in England.(10) On the other hand, they are told that weight gain is a natural part of puberty. This dichotomy can lead to confusion and reactive behaviours - for example, about 20% of all females aged between 12 and 18 engage in unhealthy "dieting" behaviours.(11)

Measuring childhood obesity
Measuring obesity in childhood is more complex than measurements in adulthood, due to the developmental issues outlined above. In terms of definitions, adult obesity is defined using the standard BMI - weight in kilograms divided by the square of height in metres (kg/m2), with a simple definition of obesity as a BMI >30.0kg/m2.(12) The Scottish Intercollegiate Guidelines Network (SIGN) suggests childhood obesity should be defined as a BMI >98th centile using the UK 1990 reference chart.(13) Simple measures to diagnose obesity in adulthood are more problematic to use in childhood, and therefore multiple measures should be used, such as BMI percentile, age and sex match. This is mainly due to the variation in growth throughout childhood, which ensures that a simplistic definition of obesity, which is unrelated to age, sex or ethnic background, is not effective.
The United Nations (UN) Convention on the Rights of the Child (Article 24) requires countries to "recognise the right of the child to the enjoyment of the highest attainable standard of health and to facilities for the treatment of illness and rehabilitation of health", and to "strive to ensure that no child is deprived of the right of access to such healthcare services".(14) This suggests that not only should services be delivered to respond to acute health needs in a reactive manner, but also that proactive support for children and young people to help them develop healthy habits and lifestyles should be offered. This means that we have a duty of care to offer support and management strategies for children who are obese or sedentary.

Approaches
The most effective approaches are likely to be holistic family-based services, as lifestyle choices made in childhood are usually based on family, societal and cultural norms within the sociocultural close environment.
Therefore management strategies for preventing and reducing obesity in children and adolescents should be holistic therapeutic interventions that involve the whole family. Often a child will have limited control over exercise and activity choices, so the efficacy of any intervention will be reduced if the controllers of these choices are not involved and actively supportive.
Management of obesity in growing children should routinely aim not for the child to lose weight, but for the child to maintain weight while height increases, or for weight to increase at a reduced rate compared with height growth rate, unless the child is under the care of a specialist team. It is essential that the child is not in zero balance of energy in/out for continued growth and healthy development, so the most appropriate aim is for the child to maintain current weight while height increases.
A systematic review of effective interventions to improve uptake of physical activity interventions among children found tentative evidence to support the use of the following:(15)

  • Education and provision of equipment for monitoring TV or video game use.
  • Engaging parents in supporting and encouraging their children's physical activity and providing opportunities for family participation.
  • Multicomponent, multisite interventions using a combination of education in the classroom, improvements in school PE and home-based activities.

This suggests that, for most practitioners, supporting family interventions may be the most practical and simple method of improving family wellbeing, improving health outcomes for children and their families at the same time. When a nurse or other practitioner is working with overweight or obese children, then it is essential that this is done within the context of family support.

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References

  1. DH. Health survey for England 1995. London: HMSO; 1996.
  2. DH. Health survey for England 2001. London: HMSO; 2002.
  3. Donaldson L. At least five a week: evidence on the impact of physical activity and its relationship to health. A report from the CMO. London: TSO; 2004.
  4. DH. Health survey for England 2002. London: TSO; 2003.
  5. Wardle H. Editor. Obesity in children under 11. National statistics. London: DH; 2005.
  6. Vanhala M, et al. Relation between obesity from childhood to adulthood and the metabolic syndrome: population-based study. BMJ 1998;317:319-20.
  7. Zeller B, et al. Psychological adjustment of obese youth presenting for weight management treatment. Obes Res 2004;12:1576-86.
  8. National Heart, Lung and Blood Institute. Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults. The evidence report. Bethesda, MD: The Institute; 1998.
  9. British Medical Association. Adolescent health. London: BMA; 2003.
  10. Wang Y, Lobstein T. Worldwide trends in childhood overweight and obesity. Int J Pediatr Obes 2006;1:11-25.
  11. American Psychological Association. Developing adolescents: a reference for professionals. Washington, DC: APA; 2002.
  12. Cole TJ, et al. Body mass index reference curves for the UK, 1990. Arch Dis Child 1995;73:25-9.
  13. Scottish Intercollegiate Guidelines Network (SIGN). Management of obesity in children and young people. A national clinical guideline. Sign publication 69. Edinburgh: SIGN; 2003. Available from: http://www.sign.ac.uk
  14. UN. Convention on the rights of the child (Article 24). New York: ICCPR; 1996.
  15. Brunton G, et al. Children and physical activity: a systematic review of barriers and facilitators - executive summary. London: EPPI-Centre, Social Science Research Unit, Institute of Education, University of London; 2003.