I have been getting dizzy when standing for occasionaly for more than a year. It has become quite frequent (a few times a day) and more severe lately. I feel fine in the morning and by afternoon it is happening. Seems to occur after sitting and working on the computer for a while. I will feel fine, wil get up and start wwalking. After a bit I get quite dizzy and sometimes have to stabalize myself and wait it out. I also get hot and start to sweat when this happpens.