Maximal oxygen uptake is the major performance limiting factor in endurance sports.
Sophisticated training methods have been developed to increase this variable. On the
other hand, attempts have been made to improve maximal oxygen uptake by artificial
means: blood doping and the misuse of recombinant human erythropoietin have beneficial
effects on aerobic exercise capacity. Both methods have been banned by international
sporting federations. A new class of substances might represent the next step of fraudulent
improvement of the maximal oxygen uptake: artificial oxygen carriers, such as solutions
based on recombinant, bovine or human hemoglobin and perfluorocarbon-emulsions have
been shown to improve oxygen delivery to the muscle. Hemoglobin-based solutions improve
aerobic exercise capacity in animal and human testing. Both substances have potentially
lethal side effects including renal toxicity, increased systemic and pulmonary blood
pressure and impairment of the immune system. Hemoglobin-based carriers can be detected
in drug testing with routine laboratory tests based on the detection of free hemoglobin.
Perfluorocarbon is not metabolized by the body and exhaled through the lung and can
be measured with chromatography. No screening for these substances in drug tests has
been performed so far. International sporting federations should be aware of this
new, emerging doping threat.
Blood substitutes, performance, hemoglobin, perfluorocarbon, sport, doping.
