Anemia is the result of an abnormally low number of red blood cells or a low hemoglobin level. Symptoms of anemia include pale skin, fatigue, weakness and loss of energy, rapid heartbeat and shortness of breath, particularly with exercise. Other symptoms can include dizziness, headache, cold hands and feet, etc. Anemia is most often caused by an iron or Vitamin B12 deficiency, a disease of the bone marrow or external and internal (digestive) blood losses. Hereditary diseases can also accelerate the destruction (hemolysis) of red blood cells as well as the ability of hemoglobin to carry oxygen. The diagnosis of anemia typically begins with examining the results of a whole blood count.