Controversial new research suggests that doping with recombinant human erythropoietin (EPO) – a behaviour that has brought down many elite cyclists – may not enhance racing performance.
The Dutch study published in Lancet Haematology found EPO provided a small benefit in terms of maximal performance in the laboratory that did not translate into an advantage in a real-life cycling race.
However EPO was still in the frame for potentially increasing the risk of thrombosis in healthy and supremely fit athletes.
The randomised controlled trial of weekly EPO injections versus placebo in highly trained but non-competitive male cyclists found EPO was associated with increases in hemoglobin, maximal power output and VO2 max after eight weeks.
However submaximal exercise testing showed no difference between the two groups of cyclists.
The researchers said the very limited amount of evidence for EPO in the past was based on uncontrolled studies conducted at high intensity that would quickly lead to exhaustion.
“By contrast, submaximal tests are at intensity levels that can be maintained for a long period of time (>20mins), which is the level at which cyclists perform most of the time.”
The study also found no advantage from EPO in a road race to the summit of Mont Ventoux in France (1hr 40 min 32 sec v 1hr 40min 15 sec).
‘These outcomes indicate that the amount of performance increment in a maximal test might not be immediately translated to a real-life situation.”
While the authors acknowledged their findings might not be applicable to professional cyclists, some exercise physiologists have been critical of the study.
Dr Rod Child, of the Elite Sports Group in the UK, said oxygen-carrying capacity could be more of a performance determinant in professional versus recreational athletes.
“The limiting factor to performance in recreationally fit subjects is likely to be different to Tour de France riders, who train and race for 4 to 5 hours a day,”
And there is contention over the researchers’ argument that submaximal effort is more important than maximal effort.
The study found no significant differences between the two groups, in vital signs, adverse events and most haematological measures.
However endothelial function markers E-selectin and P-selectin – ‘cell adhesion molecules that play a crucial role in thrombogenesis and inflammation’ – were increased in the EPO group.
The researchers said the widespread and uncontrolled use of EPO in athletes suggested they were at an increased risk of cardiovascular events.