Importance of physical activity

Physical activity is important for children to help prevent weight gain, to support optimal bone growth and to avoid disease risk factors such as high blood pressure and high cholesterol. There is also evidence that increased physical activity is associated with better psychological health in children, with gains in well being that are independent of social class and health status. In addition, being physically active and playing provides children with the opportunity for developing creative and social skills (1).

Although children are generally more active than adults, many children are not taking part in sufficient physical activity to protect their health. The PEACH Project aims to explore factors in children’s environments that act as barriers or facilitators to activity.

Decline in active travel

The way in which children travel to school is seen as a key area in which children have reduced the amount of physical activity they engage in over the years.  An increasing number of journeys are now taken by car, rather than children travelling on foot or by bike (2). The benefit of active travel seems to go beyond the actual journey as children who walk to school have also been found to be more active after school, although the reasons for this are currently unknown (3). The questionnaires used in PEACH will help unravel details of the relationship between active travel and physical activity.

Playing out

“Outdoor play makes a major contribution to children’s overall level of physical activity, including playing in the street”

(Department of Health: A Physical Activity Action Plan, 2005).

The feasibility study, prior to the main PEACH study, revealed that higher activity is associated with time spent outdoors.  Factors that may limit time spent outdoors include high traffic density, negative perceptions of neighbourhood or the accessibility of open spaces.  The combined results from the GPS watches and activity monitors will allow us to see where children go when they are outdoors and the amount of activity that takes place in different locations.  The questionnaires will allow us to assess how real or perceived aspects of the environment impact on children’s outdoor play.

Eating behaviour

Adolescence is a key period when young people start to make independent decisions about their lifestyle, with increased consumption of unhealthy foods and dropout from physical activities.  However further research into the determinants of the food and snack choices they make is still needed.  The majority of work investigating the environmental correlates of eating behaviour in adolescents has focused on investigating factors at the household level, with little investigating the influence of physical, school or neighbourhood environmental factors (4).  The PEACH Project will provide evidence to close some of the gaps in current knowledge in this area and lead to the development of improved theoretical models that can be used to identify testable targets for intervention.


Cortisol is a steroid hormone that is produced by the adrenal glands which helps to control blood sugar levels and to fight inflammation. Research has shown that cortisol levels follow a distinct daily pattern. When you wake up there is a sharp increase in cortisol then, throughout the day, the levels decrease. Cortisol is at its lowest late at night. Cortisol is also a key indicator of stress level. An increase in cortisol is part of the body's natural response to stress and measuring it will give an accurate measure of stress level. Little research has been carried out with regard to stress levels in adolescence. The PEACH and PEAR projects are looking into whether how adolescents interact with the physical environment has an influence on their stress levels. For example the projects are investigating whether more time spent outdoors is related to having lower stress levels and whether this varies by different outdoor environments.


1. Department of Health.  2004.  At least Five a Week.  Evidence on the impact of physical activity and its relationship to health.  A report from the Chief Medical Officer.  London: Department of Health

2. National Travel Survey 2003.  London: Department of Transport, Local Government and the Regions.

3. Cooper, A.R., Page, A.S., Foster, L.J. & Qahwaji, D. (2003).   Commuting to school.  Are children who walk more physically active?  American Journal of Preventive Medicine.  25(4), 273-276.

4. van der Horst, K., Oenema, A., Ferreira, I., Wendel-Vos, W., Giskes, K., van Lenthe, F. and Brug, J. (2007).  A systematic review of environmental correlates of obesity-related dietary behaviours in youth.  Health Education Research.  22(2), 203-226.


The PEACH Project is funded jointly by the National Prevention Research Initiative (NPRI) and the World Cancer Research Fund (WCRF).

The NPRI funds research aimed at improving health and preventing diseases including cancer, heart and circulatory diseases, diabetes, obesity and stroke.  The Initiative supports research on behaviours associated with significant risks to health, such as poor diet and physical inactivity, and on the environmental factors that influence those behaviours.

The WCRF is dedicated to providing research on the role of diet and physical activity in the prevention of cancer. It funds around £1 million of research each year into the link between cancer and diet, physical activity and weight management. It aims to improve our understanding of the causes of cancer and how it can be prevented.


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