What causes a high red blood cell count?

A high red blood cell count may be a symptom of a disease or disorder, although it doesn’t always indicate a health problem. Health or lifestyle factors can cause a high red blood cell count.

Medical conditions that can cause an increase in red blood cells include:

Lifestyle factors that can cause a high red blood cell count include:

  • Smoking cigarettes
  • Living at a high altitude
  • Taking performance-enhancing drugs such as anabolic steroids (for example, synthetic testosterone) or erythropoietin