Blood doping is the use of techniques and/or substances to increase a perfomers red blood cell count
the simplest form is the removal of 1-2 pints several weeks before a competition, and while the body replaces it, the blood is frozen
it is then injected a few days before performance
the use of EPO is blood doping
it is most commonly done by endurance athletes
there are side effects such as:
risk of blood borne diseases