nemia is a condition that occurs when a person does not have a sufficient amount of healthy red blood cells to carry adequate oxygen to your tissues. The condition causes a person to feel very weak and fatigued. There are many types of anemia, all of which may be caused by different things. The most common cause of anemia is loss of blood. Having anemia may be temporary or long term. It may also range from mild to severe.

The signs and symptoms of anemia may vary depending on what causes it. The signs and symptoms of anemia include fatigue, weakness, pale skin, a fast or irregular heartbeat, shortness of breath, chest pain, dizziness, cognitive problems, cold hands and feet, and a headache. Symptoms may go unnoticed if a person has a very mild form of anemia. However, the symptoms often increase as the case of anemia gets worse.

What causes anemia? Anemia occurs when your blood does not have enough red blood cells. This can happen when your body does not make enough red blood cells, bleeding causes you to lose red blood cells more quickly than they can be replaced, or your body destroys red blood cells.

Most common types of anemia:

Sickle cell anemia. This is an inherited type of anemia and is caused by a defective form of hemoglobin that makes red blood cells to develop an abnormal sickle shape. These irregular-shaped red blood cells die prematurely, which causes a chronic shortage of red blood cells.

Vitamin deficiency anemias. Our bodies need folate and vitamin B-12 to produce sufficient numbers of healthy red blood cells. A diet lacking in these and other key nutrients can cause decreased red blood cell production. Some people may eat enough B-12, but their bodies aren't able to process the vitamin. This can lead to vitamin deficiency anemia, also known as pernicious anemia.

Iron deficiency anemia. Iron deficiency anemia is caused by a shortage of iron in the body. Bone marrow needs iron to make hemoglobin. Without enough iron, the body can't produce enough hemoglobin for red blood cells. This type of anemia is often caused by blood loss, such as from heavy menstrual bleeding, an ulcer, cancer, a polyp somewhere in your digestive system, and prolonged use of aspirin or drugs known as nonsteroidal anti-inflammatory drugs.

Hemolytic anemias. This group of anemias develops when red blood cells are destroyed faster than bone marrow can replace them. Certain blood diseases can cause increased red blood cell destruction. This may be inherited, or may develop later in life.