Sitting is the new smoking - a health alert in Times of India daily reads. As per research for 15 years studying the effects of sitting for long hours, it is found that sitting for more than four hours causes obesity, diabetes, high blood pressure, cardiovascular disease, multiple cancers, etc. It is advised to set an alarm to go around and have some exercise. Sitting makes metabolic system to sleep whereas small movements will help to keep metabolic system recharged.
My ex-boss (20 years ago), used to take water as soon as he comes to office and relieves pressure in half-hour to one hour. Before coming to seat, he will take a glass or two of water and resumes work. This makes him to get up again after sometime. I find this is very good method to avoid sitting for long, immersed in the work.
However, with my personal experience, I used to hold the pressure for sometime (even 3 hours) because of work pressure. I do not know the health effects, but definitely not good for the body.