July 23, 2010. Researchers from American cancer Society reported that increased death were found in people sitting longer each day. The study tracked more than 123,000 healthy men and women for 13 years. It was reported that women sitting more than 6 hours a day in their leisure times were 40 percent more likely to die sooner than women sitting less than 3 hours. The factor for men was 20%. The association was strongest for cardiovascular disease mortality.  One question is whether people sleeping more will be more likely to die earlier. If the study results were true without cofounding, what should we do ? It is likely that a school class schedule (a 10-15 minutes break of every hour), in addition to the recommended 30-60 minutes exercise, could help a lot for those that they do have to sit to work, study, write, and so on for long hours every day.