Causes

A high hemoglobin count occurs most commonly when your body requires an increased oxygen-carrying capacity, usually because:

• You smoke
• You live at a high altitude and your red blood cell production naturally increases to compensate for the lower oxygen supply there

High hemoglobin count occurs less commonly because:

• Your red blood cell production increases to make up for chronically low blood oxygen levels due to poor heart or lung function.
• Your bone marrow produces too many red blood cells.
• You've taken drugs or hormones, most commonly erythropoietin (EPO), that stimulate red blood cell production. You're not likely to get a high hemoglobin count from EPO given to you for chronic kidney disease. But EPO doping � getting injections to enhance athletic performance � can cause a high hemoglobin count.

If you have a high hemoglobin count without other abnormalities, it's unlikely to indicate a related serious condition. Conditions that can cause a high hemoglobin count include:

• Congenital heart disease in adults
• COPD (chronic obstructive pulmonary disease) exacerbation — worsening of symptoms
• Dehydration
• Emphysema
• Heart failure
• Kidney cancer
• Liver cancer
• Polycythemia vera