This is a concept map of HYpernatremia. The medical word for having too much sodium in the blood is hypernatremia. Sodium is an essential ingredient for the body's healthy functioning. The blood contains the majority of the salt in the body. It's also found in the lymph fluids and cells of the body. Hypernatremia is often minor and does not create major issues. However, correcting elevated sodium levels is critical for preventing or reversing hypernatremia-related disorders.