Not having enough time is commonly used as an excuse for not exercising. But that argument weakens when we consider that Americans, on average, spend about 30 hours each week watching television. Harvard researchers say that all this time in front of the tube appears to be tied to a rapidly increasing incidence of type 2 diabetes in the US. Their findings are published in a recent issue of Archives of Internal Medicine.

Exercise lowered diabetes risk

Almost 40,000, healthy, middle-age men completed a biennial health and lifestyle questionnaire several times between 1986 and 1996. The volunteers answered questions about their health status, diet, exercise, and television viewing habits. The researchers noted the number of men who developed type 2 diabetes during the study period.

More than 1,000 new cases of type 2 diabetes were diagnosed over the 10 years. Which men developed diabetes appeared to depend, in part, on their exercise and TV habits. In fact, the men who exercised the most reduced their risk of developing diabetes by 50%, while the men who watched the most television--over 40 hours a week--more than doubled their risk.

TV habits and good health don't mix

The amount of time volunteers chose to spend either exercising or watching television correlated with other health-related behaviors--some healthful and some not so. Men who exercised more were leaner and also less likely to smoke than sedentary men. Habitual TV viewers were more likely than those who watched little TV to eat more fatty foods and sweets, and fewer fruits and vegetables. Not surprisingly, they were also heavier, and more likely to have high cholesterol and high blood pressure.

Small changes have big effects

Some of these health behaviors independently contribute to poor health, but even after controlling for these factors, TV viewing and physical activity independently affected diabetes risk. In fact, a 2-hour daily increase in TV viewing was associated with a 20% increase in diabetes risk. And, boosting physical activity by the equivalent of a daily, very brisk, 40-minute walk resulted a 19% reduction in diabetes risk.

These findings do not indicate that TV watching causes diabetes. Rather, they add to what doctors already know--that a sedentary lifestyle increases a person's risk of developing type 2 diabetes.

Find time to move

Less movement is needed in our everyday tasks as we spend more time on the computer, working at a desk, and driving in cars. Less movement means expending less energy, which, over time can contribute to weight gain and poor health. Therefore, we need to make a conscious effort to spend some leisure time doing something physical.

These researchers found that brisk walking offered benefits comparable to more vigorous exercise like running. This is good news, because walking is convenient, inexpensive, and results in fewer injuries than other forms of exercise. Even with an accessible activity like walking, finding time to do it can be a challenge. One suggestion: turn off the television. It may suddenly become easier to find time to exercise.