RESUMEN
BACKGROUND: The link between haemoglobin and physical performance was established a long time ago and is the underlying principle of blood doping. Blood loss on the other hand decreases physical capacity. The aim of this study is to evaluate physical performance loss and underlying mechanisms following voluntary blood donation. METHOD AND PATIENTS: Eleven voluntary subjects (four female) completed a symptom-limiting cardio-pulmonary exercise test before and after blood donation (500 mL blood). RESULTS: The haemoglobin value decreased by 1.2 mg/dL (9%, p < 0.001), maximal oxygen uptake by 9% (p = 0.006), maximal work rate by 13% (p = 0.001) and duration of exercise fell from 663 down to 607 seconds (p = 0.005). Anaerobic transition occurred at 81.2% and 71.5% of maximal oxygen uptake before and after blood donation, respectively (p = 0.001). Subjects who practise recreational endurance sports appear to be more effected by endurance loss. The haemoglobin value was the only significant predictor of maximal oxygen uptake in regression analysis (p < 0.001). CONCLUSION: Maximal physical performance is impaired after blood donation. Haemoglobin decline accounts for the decreased oxygen uptake. As a consequence thereof the anaerobic transition occurs earlier. Subjects not engaged in regular sports activity did not experience a decline in their capacity. Inclusion of the haemoglobin value into equations predicting maximal oxygen uptake could improve prediction precision.
