When there is fluid build-up in several parts of the body, it leads to an increase in weight, swelling in the legs and arms, and /or fluid in the abdomen. The fluid then reaches the lungs, fills air spaces in them and cuts the amount of oxygen that gets into the blood, causing shortness of breath. At night, when you lie down, fluid can also build up in the lungs and making it hard to breathe and sleep.
Attribution: Avallain