Standing for too long will increase the blood return to the lower extremities under the influence of gravity, and this is when swollen feet occur. There are many venous valves in the veins of the lower extremities of the human body, and the presence of these valves ensures that the blood flows back in one direction. At the same time, it also ensures that when standing even under the effect of gravity, the venous blood can still return in one direction. Therefore, keeping the lower limbs down and inactive for a long time will increase the pressure on the venous valves, slowing down the rate of return, which over time will result in poor blood return and thus swelling of the lower limbs. For this kind of swelling, it is important to release the prolonged sagging state, i.e. avoid standing for a long time and do some activities to increase the blood return. At the same time, the lower limbs can be padded to reduce the pressure on the venous valves and allow a smoother blood return. In addition, you can also do massage and hot compress treatments for the feet to increase blood circulation and speed up the elimination of swelling.