Anemia develops when your blood lacks enough healthy red blood cells. The hemoglobin in the red blood cells binds oxygen and supplies it to the cells.  When your blood test indicates anemia your doctor will rule out causes such as: heavy menstruation, pregnancy, poor diet, or hereditary diseases. If none of those causes apply you will need to rule out gastrointestinal conditions such as ulcers, hemorrhoids, gastritis and cancer. 

Symptoms include: fatigue, dizziness, pale skin, leg cramps, and rapid heartbeat, shortness of breath and headache – particularly when exercising.