Why do my feet swell when i am sitting down?

Because your: Egs are in a dependent position and allow gravity to work. Try elevating legs wh en sitting if possible.

Swelling = edema: Foot swelling (= pedal edema) occurs when standing or sitting with the feet dangling (not propped up). In these positions, the feet are subject to gravity, which causes fluid retention. By propping up (elevating) your feet, you would remove the effect of gravity, thus allowing the swelling to improve. As for the causes of swelling, there are many, so finding the cause may help treat the swelling.