|Try one of these.|
According to a physician writing on the Mayo Clinic website, the health hazards of sitting cannot be overstated: "They include obesity and a cluster of conditions — increased blood pressure, high blood sugar, excess body fat around the waist and abnormal cholesterol levels — that make up metabolic syndrome. Too much sitting overall and prolonged periods of sitting also seem to increase the risk of death from cardiovascular disease and cancer."
I'd say more but since I've got to sit to do it I better not. I just returned from a dental appointment (drive time 30 minutes, of course sitting), during which I sat for about 45 minutes, then drove home. I gotta go find something to do that involves standing. Likewise, you should stop looking at your computer (or your phone or laptop or whatever) and stand up, before it's too late! As my grandmother used to say (sort of), "There's plenty of time to sit at the cemetery."