A study from Harvard School of Public Health shows that the longer women watch television, the more likely they are to become obese and develop diabetes (Journal of the American Medical Association, April 9, 2003). Lack of exercise is a strong risk factor for obesity, high blood pressure, heart disease, some types of cancer, and diabetes.
The Nurses' Health Study followed more than 50,000 women for six years, and in that time 1,500 of the women became diabetic. Those who watched the most television doubled their risk for developing diabetes. Even light activity was associated with substantially lower risk.
In this study, the women watched television from zero to more than 40 hours a week, and those who watched the most TV didn't have time to do much of anything else. People who are addicted to television should have a stationary bicycle or some other piece of exercise equipment in front of every set so they can exercise whenever they watch TV.