The average person spends between 55-57 percent of their life engaging in sedentary behaviours (4). Sedentary behaviours are defined as any sitting or lying behaviours involving low levels of movement or energy expenditure (5).  Therefore, everyday activities such as working at a desk, driving a car, watching television or using a computer are all contributors to this statistic.  Though these activities are regularly employed and appear to be relatively harmless, they are actually key contributors to the degradation of cardiovascular health. In a study conducted by Warren et al. (2010), the relationship between sedentary activity and cardiovascular disease mortality was investigated.  Participants in the study answered sedentary activity surveys and years later mortality data was obtained from the National Death Index.  Results from the study showed that participants with high sedentary behaviours had a 64-82% greater risk of dying from cardiovascular disease.  Similar results were found in another study, investigating the effects of sedentary activity on cardiovascular risk factors and cardiovascular disease (6).  Participants in the study filled out a lifestyle questionnaire, and cardiovascular risk factors were measured using standardized procedures. Results demonstrated that with every one hour/day increase in a sedentary behaviour there was an associated increase in cardiovascular disease risk.  As evident in this research, sedentary activity must be acknowledged as a serious health hazard and proper large-scale education and prevention strategies must be developed (2).

A common misconception is that sedentary activity and physical activity are on the same spectrum, with sedentary activity being on the lower end. Therefore, it is commonly believed that being physically active can counteract the negative effects of sedentary lifestyles. Instead, current research has shown evidence that sedentary activity and physical activity are completely independent behaviours, each contributing to health and disease in different and distinct ways (1). Therefore, in order to counteract the negative effects of sedentary activity, physical activity effectively plays no role. Instead, focus must be placed on reducing the sedentary behaviours themselves.

This idea concerning the independent natures of physical activity and sedentary activity is shown in research conducted by Aadahla et al. (2007). In this study the effects of TV watching, and vigorous physical activity on several cardiovascular disease risk factors (body mass index, waist circumference, waist/hip ratio, serum lipids and blood pressure) were examined. Information concerning participant’s sedentary activity and physical activity time was collected using a self-report questionnaire. In order to control for any external contributive variables, the questionnaire included questions on participant smoking status, dietary habits, alcoholic intake and age. Furthermore, cardiovascular risk factors were assessed through physical examinations and the data collected was used to calculate the10-year absolute risk for heart disease. Associations between sedentary activity, physical activity, and cardiovascular health were then assessed. Results showed not only that sedentary activities are different types of behaviors than physical activities, but also that sedentary activity contributes to different types of cardiovascular disease risk factors.

In order to reduce the risk of cardiovascular disease induced by high sedentary activity, Hamilton et al. (2008) recommended the development of sedentary activity guidelines. In 2011 Canadian Sedentary Behaviour Guidelines were created for children and youth between the ages of 5 and 17 (3). These guidelines are the first evidence-based guidelines created, and provide critical and relevant recommendations for this age group. The guidelines recommend no more than 2 hours of screen time daily and provide suggestions for limiting sedentary time related to transportation and indoor activities (3). Though these guidelines are an important step forward to reducing sedentary activity, guidelines are still needed for older populations. Furthermore, it is crucial that information concerning sedentary activity and cardiovascular disease is made more easily available, and communicated in a large-scale public manner. Too much sedentary activity can be dangerous and negatively effect health, however with the right tools it is a simple problem to reduce. With straightforward and easily understandable guidelines, as well as proper education and promotion, risks induced by sedentary activity can be significantly decreased.

 

 

References:

1.Aadahla, M., Kjærc, M., & Jørgensena, T. (2007). Influence of time spent on TV viewing and vigorous intensity physical activity on cardiovascular biomarkers. European Journal of Cardiovascular Prevention and Rehabilitation, 14, 660–665

2.Hamilton, M. T., Healy, G. N., Dunstan, D. W., Zderic, T. W., & Owen, N. (2008). Too Little Exercise and Too Much Sitting: Inactivity Physiology and the Need for New Recommendations on Sedentary Behavior. Curr Cardiovasc Risk Rep, 2(4), 292–298.

3.Tremblay, M. S., LeBlanc, A. G., Janssen, I., Kho, M. E., Hicks, A., Murumets, K., Colley R. C., & Duggan, M. (2011). Canadian Sedentary Behaviour Guidelines for Children and Youth. Applied Physiology, Nutrition, and Metabolism, 36(1), 59-64.

4.Warren, T. Y., Barry, V., Hooker, S. P., Sui, X., Church, T. S., & Blair, S. N. (2010). Sedentary Behaviors Increase Risk of Cardiovascular Disease Mortality in Men. Med Sci Sports Exerc, 42(5), 879–885.

5.Wilmot, E.G., Edwardson, C. L, Achana, F. A., Davies, M. J., Gorely, T., Gray, L. J., Khunti, K., Yates, T., & Biddle S. J. H. (2012). Sedentary time in adults and the association with diabetes, cardiovascular disease and death: systematic review and meta-analysis. Clinical and Experimental Diabetes and Metabolism.

6.Wijndaele, K., Brage, S., Besson, H., Khaw, K. T., Sharp, S. J., Luben, R., Bhaniani, A., Wareham, N. J., & Ekelund, U. (2011) Television Viewing and Incident Cardiovascular Disease: Prospective Associations and Mediation Analysis in the EPIC Norfolk Study. PLoS ONE 6(5): e20058.