“Pinpointing just exactly how long or frequent these breaks need to be is still up for investigation. More recent research show signs of improved glucose metabolism with one minute and 40 seconds of walking every 30 minutes for a nine-hour sitting period, as well as two-minute bouts of light-intensity treadmill walking every 20 minutes throughout a five-hour sitting period. In short, getting up and walking around at least twice an hour can keep your skeletal muscles turned on and lower the risk of disease.”
Link: Why not even exercise will undo the harm of sitting all day—and what you can do about it