1. Introduction
2. What is blood doping?
3. How does it work?
4. Respiratory physiology
5. The physiology of endurance sports
6. Ventilation during endurance sports
7. Cardiac output during endurance sports
8. Aerobic metabolism during endurance sports
9. Conclusion - blood doping kills
10. References

Blood doping first came to the attention of a wider public following the 1972 Munich Olympics, when a double gold medallist reported he had used the procedure prior to the games. The ergogenic effects of blood doping were to increase maximal oxygen uptake during endurance activities, by increasing the amount of circulating haemoglobin.

Ekblom (1972) described the procedure explicitly. 1-4 units of an athlete's blood are removed over a 3-8 week period and stored in a freezer. These stored blood cells are then re-infused to the athlete (autologous transfusion) 1-7 days before the event. This procedure produces an increase of up to 20% in red blood cells and haemoglobin, which remains elevated for about two weeks. The increased haemoglobin level produces an increase in the oxygen carrying capability of the athlete's circulatory system.

More recently, some endurance athletes have taken to intravenous injection of recombinant erythropoietin (EPO) to get similar effects to the blood doping method mentioned above. Human erythropoietin is produced naturally by the kidneys. The kidneys release an enzyme - erythrogenin - that transforms plasma globulin to erythropoietin, under conditions of hypoxia (for this reason exposure to altitude has a similar physiological effect). Erythropoietin is a glycoprotein which stimulates erythropoiesis in bone marrow and raises the level of circulating haemoglobin. This has been shown to increase aerobic power (Ekblom and Berglund, 1991) and thus endurance performance. Casoni et al (1993) also demonstrated an increase in the levels of circulating red blood cells and haematocrit.

How does it work? >