Lower leg and foot swelling also known as edema is most often caused by an abnormal fluid build-up that flows downhill and pools in the lowest parts of your body. Excess fluid retention can be triggered by many things, including eating too much salt, heat, drinking alcohol, or standing for a long period of time. You might also be prone to it if you are older or overweight. If your edema is not caused by a medical problem, here's what you can do to get some relief. Cut down on your salt intake, put your feet up, go for a walk, move your ankles or do some stretching exercises.