The biggest possibility of swelling of feet after sitting for a long time is the occurrence of lower extremity venous valve insufficiency, lower extremity venous valve insufficiency is divided into deep venous valve insufficiency, and superficial venous valve insufficiency, both of which can cause edema, but superficial venous insufficiency is often accompanied by varicose veins. This condition occurs because of the destruction of the valves in the lower limbs, so that the blood flows backward in the process of returning to the heart, and because of the obvious weakening of the muscular pump of the calf after a long period of sedentary life, it leads to the accumulation of fluid in the calf and the foot and the swelling of the foot. Once this condition occurs, vascular ultrasound should be carried out as early as possible to clarify the condition, and after the condition is clarified, surgical treatment can be chosen according to the results of the ultrasound examination, or active conservative treatment.