One reason for swelling (edema) of the lower extremities is simply due to the basic fact that our bodies contain a great deal of liquid. Every cell of our bodies is bathes in watery liquid - fluids that cycle constantly back and forth between our bloodstreams and the gaps between our tissue cells, gaps that are called the interstitial space.

When there is a disruption of any sort in the flow of fluid between this space and our bloodstream, the result can be some swelling in our legs, ankles and feet. And there are of course a number of things which can lead to such a disruption.

Some causes are well known. Varicose veins, for example, are veins that have been stretched our and that are no longer functioning efficiently. They do a poor job of helping move the blood back to your heart, resulting in a backup or pooling of blood in your legs, which leads to excess interstitial fluid that causes swelling.

Most women know that leg swelling is common during pregnancy, but a number of other conditions can also contribute to leg swelling or edema. Standing for long periods, especially in hot weather can cause swelling. People with congestive heart failure often have trouble with swollen legs. This is because the weakened heart muscle is unable to operate efficiently as a pump, which leads to blood stagnating in the veins, especially in the extremities, such as the legs and feet.

Other conditions that can lead to leg, ankle and foot swelling include malnutrition, disorders of the liver, kidney, or intestines and even very common health problems such as allergies, insect bites or bacterial infections. A more serious health condition which can lead to swelling is a blockage of the lymphatic system (lymphedema) resulting from cancer or lymph gland inflammation.