There are other causes besides what happens within the body in the blood cells. Other factors that can cause an excess amount of hemoglobin are: * Smoking (which may result in low blood oxygen levels) * Higher altitudes where your red blood cell production naturally increases to compensate for the lower oxygen supply there Specific disorders or other factors that may cause a high hemoglobin count include: * Lung disease * Heart disease * COPD (chronic obstructive pulmonary disease) * Dehydration * Emphysema * Heart failure * Kidney cancer * Liver cancer * Other types of heart disease * Other types of lung disease * Polycythemia vera, a disorder in which your body makes too many red blood cells. It can cause headaches, fatigue, and shortness of breath.
Hemoglobinemia
Thalassemia
Sideroblastic anemia
Myelophthisic anemia
Alpha-thalassemia
Megaloblastic anemia
Beta thalassemia
Paroxysmal nocturnal hemoglobinuria