Here is another study showing that sitting for prolonged periods of time is not good for the body and for health. Scientists are increasingly warning that sitting for prolonged periods even if you also exercise regularly could be bad for your health. After two hours of sitting, the metabolism starts to slow down along with the circulatory system. After four hours of sitting, the body starts to send harmful signals in that genes regulating the amount of glucose and fat in the body start to shut down which may end up depositing more fat in the body. If you do have a job where you sit a lot, try getting up every hour to at least walk around your desk or the office.