Elevated sodium levels can become quite dangerous for people because the body's responses can lead to stroke, heart attack, high blood pressure and heart failure, notes Harvard School of Public Health. The body retains water to dilute the sodium, adding excess volume to blood in the circulatory system.
The first line of defense against excess sodium is the kidneys, but they often have difficulty dealing with the high levels. The body absorbs water to compensate, adding the water to the volume in the bloodstream. This gives the heart and blood vessels a higher level of pressure and more of a workload. Over time, the blood vessels can stiffen, causing such conditions as stroke, high blood pressure and cardiac arrest, as stated by Harvard School of Public Health.
Additional concerns connected to excess sodium include damage to the kidneys, aorta and heart even when blood pressure does not elevate. Bone damage is a possible consequence as well. When high blood pressure does occur, it is one of the major causes for cardiovascular disease. In China alone, high blood pressure kills more than 1 million people each year, and worldwide, high blood pressure is the main cause of half of all heart disease cases and two-thirds of all strokes, according to Harvard School of Public Health.