Causes

High red blood cell count may be caused by low oxygen levels, kidney disease or other problems.

Low oxygen levels

Your body may increase red blood cell production to compensate for any condition that results in low oxygen levels, including:

• Heart disease (such as congenital heart disease in adults)
• Heart failure
• A condition present at birth that reduces the oxygen-carrying capacity of red blood cells (hemoglobinopathy)
• High altitudes
• COPD (chronic obstructive pulmonary disease) exacerbation — worsening of symptoms
• Pulmonary fibrosis (scarred and damaged lungs)
• Other lung diseases
• Sleep apnea
• Nicotine dependence (smoking)

Performance-enhancing drugs

Certain drugs stimulate the production of red blood cells, including:

• Anabolic steroids
• Blood doping (transfusion)
• Injections of a protein (erythropoietin) that enhances red blood cell production

Increased red blood cell concentration

• Dehydration (If the liquid component of the blood (plasma) is decreased, as in dehydration, the red blood cell count increases. This is due to the red blood cells becoming more concentrated. The actual number of red blood cells stays the same.)

Kidney disease

Rarely, in some kidney cancers and sometimes after kidney transplants, the kidneys might produce too much erythropoietin. This enhances red blood cell production.

Bone marrow overproduction

• Polycythemia vera
• Other myeloproliferative disorders