Water retention, also known as EDEMA, is a condition in which the body holds onto excess fluid. This can cause swelling in the extremities, such as the hands, feet, and ankles. It can also cause weight gain, shortness of breath, and fatigue. In some cases, water retention can be a sign of an underlying medical condition, such as kidney or heart disease. Treatment for water retention depends on the underlying cause and may include lifestyle changes, medications, or surgery.