Smoking is hazardous to your health, but according to a series of papers published in the journal Lancet, physical inactivity is just as deadly. In fact, of the 57 million deaths recorded worldwide in 2008, researchers attributed 5.3 million of them to lack of exercise.

While spending the whole afternoon watching your favorite re-runs isn’t directly responsible for the one in 10 premature deaths tallied globally every year, it may still increase your risk of developing four major diseases: heart disease, Type 2 diabetes, breast cancer, and colon cancer.

In the division of preventive medicine at Brigham and Women’s Hospital, scientists led by I-Min Lee used population attributable fraction (PAF) to measure the contribution of certain risk factors to particular diseases. In theory, it would show researchers how many diseases could be prevented if the risk factor were to decrease.

Calculating for the PAF of 123 countries on physical inactivity toward the four major diseases mentioned earlier, researchers came up with significant results. Apparently, lack of exercise was responsible for six percent of heart disease cases, seven percent of Type 2 diabetes, and 10 percent of breast and colon cancers all over the world.

And what if physical inactivity were to decrease? Theoretically, risk factors such as high blood pressure, high cholesterol, and high blood sugar would be lowered. Blood clots would become rare. Belly fat would be trimmed down which, in turn, may avert tumor growth in breast tissue. Digestion would improve and abnormal growths in the colon may become a distant memory. Statistically, if physical inactivity were to decrease by just 10 percent, as many as 533,000 deaths may be avoided.

Exercise, it seems, is the key to a long life. But as simple as this solution may be on paper, the opposite holds true in real life. Guidelines say that 150 minutes of physical activity each week is enough to stay in good shape but unfortunately, people have a hard time even setting 30 minutes aside for a quick run. According to Pedro Hallal of the Federal University of Pelotas, 31 percent of adults worldwide and four out of five teens just aren’t exercising enough.

Now is the time to change all that. With increased awareness on the dangers of physical inactivity, perhaps you could schedule a quick run before or after work. If physical inactivity were truly as dangerous as smoking, then you at least have a better chance of reducing your risk of premature death. With a combination of discipline and hard work, you may live beyond your expected years.

(Photo by Prescott Pym via Flickr Creative Commons)