Neumayr G, Pfister R, Mitterbauer G, Gaenzer H, Joannidis M, Eibl G, Hoertnagl H
Institute of Sports Medicine, University Clinics of Innsbruck, Austria.
Int J Sports Med. 2002 Apr;23(3):158-61. doi: 10.1055/s-2002-23169.
Knowledge is sparse about the extent of potential dehydration due to prolonged strenuous cycling and its haematological acute effects on the haematocrit (Hct) in study populations credibly not taking any kind of doping. With increasing training load levels of Hct and haemoglobin (Hb) decrease in both amateurs and professionals as a long-term consequence due to expanded plasma volume (PV). On a short-term basis, however, counteracting dehydration potentially brought about by endurance exercise may cause a rise in Hct bringing competitive cyclists into conflict with the current condition regulations and Hct cut-off of 50 % set by the International Cycling Union (UCI) in its fight against erythropoietin (rhEPO) doping. On the other hand adequate and sufficient fluid substitution being substantial for a successful endurance performance should prevent any pronounced Hct rises. To study the haematological acute effects of prolonged strenuous cycling we measured Hct, Hb, red blood cell (RBC) count and plasma protein in a reliably 'clean' population of 38 well-trained male amateur cyclists before, immediately after and one day after an extraordinary ultramarathon. The pre-race levels of Hct, Hb and RBC count were placed in the lower range of normal distribution and well below the Hct cut-off limit of the UCI. Immediately post-exercise the mean levels of Hct, Hb, RBC count and protein remained unchanged. One day after race, however, all four parameters significantly dropped by 3 %, 6.7 %, 6.5 %, 9.9 % respectively (p < 0.001), indicating marked post-exercise PV expansion. The calculated percentage increase in PV was 11.9 %. No evidence for coexisting exercise-induced haemolysis was found. Our study shows that in "clean, rhEPO-free" amateur cyclists who involve in strenuous marathon cycling the haematological short-term effects of extraordinary marathon cycling consist in considerable PV expansion making Hct values fall on the following day. The findings - gained from amateurs though - suggest that despite all its disadvantages the UCI Hct cut-off represents an appropriate means to discourage from excessive rhEPO doping at least as long as the available direct methods for detecting this kind of misuse are not yet applied by the international sports federations.
对于长时间剧烈骑行导致的潜在脱水程度，以及在可靠地未使用任何兴奋剂的研究人群中其对血细胞比容（Hct）的血液学急性影响，目前了解甚少。随着训练负荷的增加，由于血浆量（PV）增加，业余和专业运动员的Hct和血红蛋白（Hb）长期都会下降。然而，在短期内，耐力运动可能导致的脱水产生的反作用可能会使Hct升高，这使得职业自行车运动员与国际自行车联盟（UCI）在打击促红细胞生成素（rhEPO）兴奋剂时设定的当前状况规定和50%的Hct临界值产生冲突。另一方面，充足且足够的液体补充对于成功的耐力表现至关重要，应可防止Hct显著升高。为了研究长时间剧烈骑行的血液学急性影响，我们在一场特别的超级马拉松比赛前、比赛结束后立即以及比赛后一天，对38名训练有素的男性业余自行车运动员这一可靠的“清白”人群测量了Hct、Hb、红细胞（RBC）计数和血浆蛋白。赛前Hct、Hb和RBC计数水平处于正常分布的较低范围，且远低于UCI的Hct临界值。运动后即刻，Hct、Hb、RBC计数和蛋白质的平均水平保持不变。然而，比赛后一天，所有这四个参数分别显著下降了3%、6.7%、6.5%、9.9%（p < 0.001），表明运动后PV显著扩张。计算得出的PV增加百分比为11.9%。未发现同时存在运动诱导溶血的证据。我们的研究表明，在参与剧烈马拉松骑行的“清白、无rhEPO”业余自行车运动员中，特别马拉松骑行的血液学短期影响在于PV显著扩张，使得第二天Hct值下降。尽管这些发现来自业余运动员，但表明尽管有所有缺点，UCI的Hct临界值仍是一种合适的手段，至少在国际体育联合会尚未应用可用的直接检测此类违规行为的方法之前，可抑制过度使用rhEPO兴奋剂。
