Anemia
Anemia is a homeostatic imbalance in the blood when there is low hematocrit, or lower count of red blood cells. Symptoms of anemia may be weakness, extreme fatigue, and confusion. Anemia can be caused from iron deficiency from a low-iron diet, excessive bleeding, or even lead poisoning. Another cause of anemia may be sickle-cell anemia. Sickle-cell anemia is caused by one amino acid change in DNA. The imbalance is called "sickle-cell," because the shape of the red blood cell takes on the look of a sickle. Having sickle-cell anemia can reduce the ability to exercise and makes transporting oxygen very difficult in the body.
Blood Doping
Blood doping is an illegal crime in sports worldwide. Athletes use blood doping to increase their athletic performance by adding more blood to their bodies. Blood doping magnifies athletic performance, because with more red blood cells in the body, the more oxygen can be transferred. The downfall of blood doping is the increase in red blood cells makes it difficult on the heart to pump. Blood doping is illegal, because it is no different than any other body enhancement, such as steroids. Another risk of blood doping is having the wrong type of blood entered into your system. When this occurs the red blood cells in your body will attack the new ones and decrease your red blood cell count.