SHR # 2863:: Sodium Restriction In Heart Failure? - Justin A. Ezekowitz, MBBCh, MSc - For years physicians have ordered their patients to restrict sodium for a variety of reasons. High blood pressure, cardiac function and heart failure are a few. The theory is that sodium attracts water and that fluid retention increases the blood volume thus increasing pressure in the heart and blood vessels. A recent study may show why this isn't working.