Too much sitting may be bad for your health

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Lack of physical exercise is often implicated in many disease processes. However, sedentary behavior, or too much sitting, as distinct from too little exercise, potentially could be a new risk factor for disease. The August issue of the American Journal of Preventive Medicine features a collection of articles that addresses many aspects of the problem of sedentary behavior, including the relevant behavioral science that will be needed to evaluate whether initiatives to reduce sitting time can be effective and beneficial.

"Epidemiologic and physiologic research on sedentary behavior suggests that there are novel health consequences of prolonged sitting time, which appear to be independent of those attributable to lack of leisure-time physical activity," commented Neville Owen, PhD, Head of Behavioural Epidemiology at the Baker IDI Heart and Diabetes Institute, Melbourne, Australia. "However, behavioral research that could lead to effective interventions for influencing sedentary behaviors is less developed, especially so for adults. The purpose of this theme issue of the American Journal of Preventive Medicine is to propose a set of perspectives on 'too much sitting' that can guide future research. As the theme papers demonstrate, recent epidemiologic evidence (supported by physiologic studies) is consistent in identifying sedentary behavior as a distinct health risk. However, to build evidence-based approaches for addressing sedentary behavior and health, there is the need for research to develop new measurement methods, to understand the personal, social, and environmental factors that influence sedentary behaviors, and to develop and test the relevant interventions."

Contributed by an international, multidisciplinary group of experts, papers include a compelling cross-national comparison of sedentary behavior, several reports on trends in sedentary behavior among children and a discussion of the multiple determinants of sedentary behavior and potential interventions. The collection is particularly noteworthy because it:

- Represents a major advance in collecting and analyzing current research on sedentary behavior, especially the relevant behavioral science that must be better understood if such behaviors are to change over time to improve health outcomes.
- Adds "momentum" to the discussion about sedentary behavior potentially being an independent risk factor for disease, ie, when examined specifically and distinctly from the effects of physical activity or exercise in large prospective studies, those who sit more often are found to have a greater risk of premature death, particularly from heart disease.
- Indicates that, despite the need for additional research on potential cause-and-effect relationships, and particularly the underlying physiological mechanisms that might be at play, there is now a growing momentum to address the issue of sedentary behavior more proactively in health promotion and disease prevention.
- Shows that children's current and future health is particularly at risk given that they spend substantial amounts of their day sitting at school, at home and through transport, and that new technologies and entertainment formats may exacerbate this problem. Thus, it is critical to understand what influences children to sit so much, so we can develop effective interventions.

Has particularly important implications for workplace environments and the potential health benefits of re-engineering workplace design and processes, especially in developed countries where most adults spend most of their workday sitting. These concerns have an important economic, population health and social equity context, even though the studies did not include economic or sociocultural research on this topic specifically.

The authors highlight the fact that broad-reach approaches and environmental and policy initiatives are becoming part of the sedentary behavior and health research agenda. In this context, mass media health promotion campaigns are already beginning to incorporate messages about reducing sitting time in the home environment, together with now-familiar messages about increasing physical activity. In the workplace, there is already active marketing of innovative technologies that will act to reduce sitting time (such as height-adjustable desks). Community entertainment venues or events may also consider providing non-sitting alternatives. Community infrastructure to increase active transport (through walking or biking) is also likely to reduce time spent sitting in cars. If such innovations are more broadly implemented, systematic evaluations of these "natural experiments" could be highly informative, especially through assessing whether changes in sedentary time actually do result.