Physical inactivity carries heavy weight worldwide

August 7, 2012

With the start of the 2012 Olympic and Paralympic Games in London, scientists writing in the July 18 issue of The Lancet call for doctors to recognize exercise as a “fifth vital sign” as one of the key indicators of health used by doctors and other health care professions.

The publication is part of a series in The Lancet on sports and exercise medicine and how sport and exercise contribute to the health of a nation.

Temperature, blood pressure, pulse and respiratory rate have long been considered the vital signs of health. But researchers writing in The Lancet suggest that that if health professionals were to consider exercise levels as a “vital sign”, they could provide more help for patients to adopt exercise regimes. This could result in increases in the number of people who regularly exercise, in the same way that smoking cessation advice has resulted in reductions in the number of people who smoke in many countries.

Dr. Steve Blair of the Arnold School of Public Health is a co-author on a paper in The Lancet special issue that reported that physical inactivity worldwide causes about 6 percent of the burden of disease from coronary heart disease; 7 percent of type 2 diabetes; 10 percent of breast cancer, and 10 percent of colon cancer.

The study, titled “Effect of Physical Inactivity on Major Non-Communicable Diseases Worldwide: An Analysis of Burden of Disease and Life Expectancy, also found that inactivity causes 9 percent of deaths world-wide, or more than 5.3 million of the 57 million deaths that occurred worldwide in 2008. To put this in perspective, smoking causes ~5 million deaths world-wide each year.

Physical inactivity has a major health effect worldwide, said Blair, a faculty member in the Arnold School’s Department of Epidemiology and Biostatistics and Department of Exercise Science.

“Today’s increasing rates of diabetes, cardiovascular disease, some cancers, and many other chronic health problems are caused by sedentary lifestyles” he said. “If we were to get more people to be physically active, then the health of children and adults would improve substantially.”

Blair attended the July 17 news conference in London for The Lancet’s special issue, which has received international attention.

“In this article, we point out that ancient physicians, including those from China in 2600 BC and Hippocrates around 400 BC, believed in the value of physical activity for health. By the 20th century, however, a diametrically opposite view -- that exercise was dangerous -- prevailed instead,” Blair said.

In fact, the study points out, during the early 20th century, complete bed rest was prescribed for patients with acute myocardial infarction. But in the 1950s, the first epidemiological studies were done to examine physical inactivity and chronic disease risk. Since then, researchers around the world have found that physical activity is linked to reduced rates of coronary heart disease, high blood pressure, stroke, breast and colon cancers, type 2 diabetes, metabolic syndrome, depression and falling. And strong evidence exists to show that physical activity increases muscle and cardiorespiratory fitness, leads to healthier body mass and composition, improves bone health and cognitive function and increases functional status.

The researchers said, “This summer, we will admire the breathtaking feats of athletes competing in the 2012 Olympic Games. Although only the smallest fraction of the population will attain these heights, the overwhelming majority of us are able to be physically active at very modest levels -- eg, 15 to 30 minutes a day of brisk walking -- which bring substantial health benefits. We must explore all avenues and support all efforts to reduce physical inactivity worldwide.”

To read more, visit http://www.thelancet.com/series/physical-activity.

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