Spring/Summer 2003    Vol. 11, Issue 1
Sedentarism Rises, Becomes Global Health Hazard
Traditionally, prevention of chronic noncommunicable diseases (NCDs) focused on tobacco control and improved diet. In its new NCD prevention strategy outlined in a 2003 report on diet, nutrition and the prevention of chronic diseases, the World Health Organization (WHO) underscores increased physical activity as a key component. This new emphasis, first introduced by WHO in 2002, is based on several facts. Firstly, convincing scientific evidence reveals that a lack of physical activity, or sedentarism, substantially increases (as much or even more than most other common risk factors) the probability of several of the most common NCDs, including cardiovascular disease (CVD), diabetes, certain cancers and obesity, a major NCD risk factor. Secondly, sedentarism is common -- more prevalent that most other NCD risk factors, and it is rapidly increasing in most countries worldwide. Thirdly, the health consequences of sedentarism can be abolished or diminished substantially by moderate, feasible physical activity. And finally, increasing physical activity to sufficient levels to benefit health at individual and population levels is possible and economical, and may confer social and environmental advantages.

The Facts
Sedentarism causes 1.9 million deaths annually around the globe; and it accounts for an estimated 8 to 10 percent of all deaths in Eastern Europe alone, where physical inactivity is particularly common. In the elderly, sedentarism increases the risk of serious bone fractures by as much as 50 percent and may accelerate loss of independence by several years. Physical inactivity also doubles the risk of becoming obese and is undoubtedly a major factor in the global obesity epidemic. Conversely, enhanced physical activity substantially attenuates the risks associated with obesity, even without significant effect on body weight.

Although it is widely accepted that 30 minutes of moderate-intensity activity a day is sufficient to maintain good cardiovascular and metabolic health, WHO recommends 60 minutes a day of moderate-intensity exercise, such as brisk walking, to maintain healthy body weight, attain greater health benefits and avoid obesity. Sixty minutes of physical activity is particularly important for people with sedentary occupations.

Currently, at least 60 percent of the world's population does not meet even the 30-minute minimum. Meanwhile sedentarism is estimated to cause about 22 percent of all ischaemic heart disease and 10 to 16 percent of all ischaemic stroke, diabetes, colon cancer and breast cancer around the globe. Sedentarism also ranks seventh among WHO's risk factors for disease burden in developed countries, accounting for 3.3 percent of disability-adjusted life years. Added to elevated blood pressure, high cholesterol, overweight levels and obesity, the disease burden attributed to sedentarism increases substantially.

The financial costs of sedentarism are also high: In Canada, it accounts for about 6 percent of total health care costs. In the United States, physical inactivity together with obesity comprised 9.4 percent of the national health expenditure (US$94 billion) in 1995.

Obstacles, Potential for Risk-Reduction and Strategies for Success
Physical inactivity continues to rise with the use of machines and automation at work, in transportation and for domestic chores. Meanwhile, few populations worldwide, including people in affluent societies, practice compensatory physical activity in leisure pursuits. In developing-country metropolises and among socially disadvantaged groups, traditions and lack of awareness are serious obstacles. In China, for example, bicycling, as a means of transportation, is rapidly decreasing -- without a compensatory increase in leisure-time physical activities because of a lack of tradition and opportunities.

This is disheartening news, especially since the risk-reduction from increased physical activity for several NCDs has been demonstrated in women and men, elderly subjects and high-risk groups. Two randomised controlled trials, one in the United States in 2002 and the other in Finland in 2001 revealed that modest changes in diet and physical activity decreased the development of new cases of type 2 diabetes by 58 percent within three years among high-risk middle-aged women and men.

Successive national physical activity programs in Finland since 1991 indicate that it is possible to maintain, and even expand, participation in leisure-time physical activities among various population groups. Several examples from major European cities demonstrate that walking and cycling as modes of transportation can be substantially increased. Bicycling grew by 7 to 16 percent in Basel, Switzerland, Graz, Austria and Hannover, Germany, and rose 29 to 43 percent in Delft, The Netherlands and Munster, Germany within a 10- to 20-year period as a result of cycling networks and traffic calming, for example. Maximum benefits, however, can be achieved only by comprehensive, long-term measures that combine individual, population and environmental approaches; meet the needs and expectations of the targeted subjects; use a variety of settings; emphasize local initiatives and actions; and support sustained collaboration among multiple partners in both governmental and nongovernmental sectors.

The first step is to win sufficient political support and commitment. This requires raising public awareness of the health benefits of physical activity. The experiences of the United States, Canada, several European countries and major international organizations such as WHO demonstrate that it is possible to apply such strategies and mobilize resources to increase health-promoting physical activity.

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