Volodymyr Bazarnyi, a scientist and an author of the health-saving method of workflow, considers it optimal to stay in one position for no more than 25 minutes.
Now, just think about how much time do you sit in front of your computer? This usually takes hours.
While you are sitting, the muscles of the neck, back, and waist do the static work. They get tired during the day even if you sit comfortably in a modern chair. In this case, it interferes with the blood supply to the organs. As a consequence, you experience fatigue, loss of concentration, and general discomfort.