Exercise as it relates to Disease/The Impact of School-based Walking Interventions on Cardiovascular Disease

This Wikibooks page contains an overview and analysis of the journal article ‘A cross-curricular physical activity intervention to combat cardiovascular disease risk factors in 11-14 year olds: 'Activity Knowledge Circuit’ by G, Knox et al (2009).

What is the background to this research
Cardiovascular disease refers to all diseases and conditionings associated with the heart and blood vessels. It is the leading cause of death worldwide, has huge implications within society and the risk factors developed during childhood have been shown to carry on through to adulthood. The prevalence of cardiovascular disease increases with age, and is higher within lower socioeconomic groups and community’s in remote areas. The main types of cardiovascular disease include coronary heart disease, stroke and heart failure. There is a clear relationship between exercise and cardiovascular disease. Exercise has shown to decrease the majority of risk factors associated with cardiovascular disease. The study produced by Knox et al. focuses on the importance of remedying cardiovascular diseases in the younger population in a cost effective and simple way.

Where is the research from?
This study was carried out by researchers from the Cardiff School of Sport, University of Wales Institute, United Kingdom. This study was funded through a grant from Sports council wales, a national organisation responsible for developing and promoting sport and active lifestyles. This would not have created a conflict of interest, however the Council is bias towards promoting exercise. The authors of this article have declared that they had no competing interests.

What kind of research was this?
This study was a Quasi-experiment consisting of two groups, an intervention group and a control group. Participants, aged 12–13 years, were assigned to a cross-curricular physical activity intervention. While maturation matched participants, aged 11–14 years, formed the control group. This type of research has previously produced modest improvements in cardiovascular diseases risk factors. Many of the studies focused on this topic have looked to improve physical activity within physical education classes, while also improving the participant's diet.

What did the research involve?
This study involved students aged 11–14 years who attended the South Wales Valley school. It aimed to implement an 18-week school-based cross-curricular exercise intervention to improve cardiovascular disease risk status, psychological well-being and motivation to exercise in 11-14 year old children. The intervention group undertook two extra sessions of exercise per week on top of their regular PE classes, for 18 weeks. During these two sessions the participants briskly walked a set course of 3,200m. Apart of this course involved educational stations set up at every 400m or 800m where the children spent 60 seconds learning the regular curriculum. If there were adverse weather conditions then the course was set up indoors. Several measurements were performed pre and post intervention for both the intervention and control group. All measurements were voluntary and the participants were allowed to withdraw at anytime. The measures from the intervention group were analysed against the control to determine the effectiveness of the intervention.

Measurements taken included:
 * Anthropometrics: height, weight, circumferences and skin folds.
 * Blood pressure: systolic and diastolic blood pressure.
 * Cardio-respiratory fitness: 20m multi-stage fitness test.
 * Questionnaires: physical activity questionnaire for adolescents, maturation status and dietary questionnaire.
 * Fasting-blood variables: total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, insulin, glucose, high-sensitivity C-reactive protein, interleukin-6, fibrinogen and adiponectin.
 * Psychological variables: motivation and well-being (mood states).

What were the basic results?
The article stated that the study produced modest improvements in cardiovascular disease risk factors. However, the article includes no results section or any of the pre and post measures produced. Due to this it is hard to say how the researchers interpreted the results and whether they over-emphasised the implications of the findings. It is hard to say that the study produced any modest improvements in cardiovascular disease risk factors, as they are not documented. However, a theme throughout recent literature indicates that exercise improves these cardiovascular disease risk factors.

Limitations
One of the main limitations evident in this study was the use of non-randomised sampling. The study compared groups of different ages, which produced questionable results, as cardiovascular risk factors have been found to increase with age. This limitation makes comparing the results between the trial groups irrelevant. Another limitation was due to the cohort size being very small, as the study was based on a small school and few year groups were involved, there were not enough participants to draw significant results from the data. If this study was conducted over many schools within the area the results could have been more reliable. Another limitation involves the socioeconomic status of the school. People of lower socioeconomic status have shown to have a higher prevalence for cardiovascular disease. Making it difficult to relate the findings to broader population.

Criticisms and Concerns
This study was produced to be a cost-effective way to reduce cardiovascular disease risk factors within school children. However, not only was the article absent of results it also did not make mention to the effects the study had on the children's education. One of the main concerns focused around this study is the effect the cross-curricular physical activity approach had on learning and the children's education. This study was highly focused on being cost effective and took little consideration into how the children would perform in comparison to other class mates who did not partake in the study. The researchers should have included a post intervention test and compared results between the intervention and control group to see if education was impacted and if the study was a viable way to implement extra physical activity. Overall, this is not a well-executed study.

What conclusions should be taken away from this research?
The main conclusion outlined within this research is that children need to be more active in everyday life. If researchers are willing to interrupt school lessons it shows that there is a serious need for higher physical activity levels throughout the population. Cardiovascular disease risk factors have been shown to improve with exercise and physical activity.

What are the implications of this research?
According to the authors, physical activity and exercise play a key role in minimising the risk factors of cardiovascular disease. However, because this article includes no evidence based results or comments about the education status of the participants post intervention it would not be recommend to implement this type of cross-curricular physical activity into other schools. Moreover, this is a great base for further research and if further studies are carried out effectively then the conclusions produced may be able to form effective school based interventions to lower cardiovascular disease risk factors.

Further Information
For more information in relation to cardiovascular disease; tips on prevention and ways to get involved, head to https://heartfoundation.org.au/.