I read an article this morning involving serious medical issues from prolonged sitting. According to a comprehensive Swedish study, people sitting for periods of 4 hours or more are at a greater risk of metabolic syndrome (a precursor of diabetes type 2), obesity, and death. It appears that the regulatory mechanisms controlling insulin and glucose shut off or down-regulate after 4 hours, another sign that sitting is so unnatural for humans. I also heard that teens, on average, spend 7.5 hours/day on computers, playing video games, and texting- a generation headed for a host of medical issues. Since most of us have to sit, there is a cool free download called e.ggtimer.com, at which you can set any time interval to remind you to take a break. I use it to get up stretch a little bit, walk around, then resume my work.
Stay well, John R Blilie, M.S.