A person with anemia has too few red blood cells. The most common symptom is a lack of energy. Why would anemia cause this symptom?
This happens because your body needs iron to make a protein called hemoglobin, which is found in red blood cells. Hemoglobin helps carry oxygen around the body. When your body doesn't have enough hemoglobin, less oxygen reaches your tissues and muscles, depriving them of energy.
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