Short-Term Effects of Prolonged Strenuous Endurance Exercise on the Level of Haematocrit in Amateur Cyclists

Abstract

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.

Haematocrit · plasma volume · cycling · endurance sports · erythropoietin doping.

References

• 1 Anonymous . Peddling drugs to the pedal pushers (Editorial).  Lancet. 1998;  352 415
• 2 Anonymous .UCI. Sporting safety and conditions regulations. Lausanne; UCI 1998 Part 13: 1-5
• 3 Costill D L, Fink W J. Plasma volume changes following exercise and thermal dehydration.  J Appl Physiol. 1974;  37 521-525
• 4 Davidson R JL, Robertson J D, Galea G, Maughan R J. Hematological changes associated with marathon running.  Int J Sports Med. 1987;  8 19-25
• 5 Eichner E R. Sports anemia, iron supplementation, and blood doping.  Med Sci Sports Exerc. 1992;  24 315-318
• 6 Ekblom B, Berglund B. Effect of erythropoietin administration on maximal aerobic power.  Scand Med Sci Sports. 1991;  1 88-93
• 7 Guglielmini C, Patracchini M, Manfredini F, Grazzi G, Ferrari M, Conconi F. Reduction of Hb levels during the racing season in nonsideropenic professional cyclists.  Int J Sports Med. 1989;  10 352-356
• 8 Halberg I, Magnusson B. The etiology of “sports anaemia”.  Acta Med Scand. 1984;  216 149-209
• 9 Kolka M A, Stephenson L A, Wilkerson J E. Erythrocyte indices during a competitive marathon.  J Appl Physiol. 1982;  52 168-172
• 10 Kujala U M, Peltonen J E, Elovainio R O. Hemoglobin and packed-cell volume in endurance athletes prior to rhEPO.  Int J Sports Med. 2000;  21 228
• 11 Lasne F, de Ceaurriz J. Recombinant erythropoietin in urine.  Nature. 2000;  405 635
• 12 Marx J, Vergouwen P. Packed-cell volume in elite athletes.  Lancet. 1998;  352 451
• 13 Maughan R J, Whiting P H, Davidson R JL. Estimation of plasma volume changes during marathon running.  Br J Sports Med. 1985;  19 138-141
• 14 Mayer G, Thum J, Cada E M, Stummvoll H K, Graf H. Working capacity is increased following recombinant human erythropoietin treatment.  Kidney Int. 1988;  34 525-528
• 15 Neuhaus D, Gaehtgens P. Haemorrheology and long term exercise.  Sports Med. 1994;  18 10-21
• 16 Pivarnik J M, Leeds E M, Wilkerson J E. Effects of endurance exercise on metabolic water production and plasma volume.  J Appl Physiol. 1984;  56 613-618
• 17 Rocker L, Kirsch B, Heyduck B, Altenkirch H U. Influence of prolonged physical exercise on plasma volume, plasma proteins, electrolytes, and fluid-regulating hormones.  Int J Sports Med. 1989;  10 270-274
• 18 Saris W H, Senden J M, Brouns F. What is a normal red-blood cell mass for professional cyclists?.  Lancet. 1998;  352 1758
• 19 Schmidt W, Biermann B, Winchenbach P, Lison S, Böning D. How valid is the determination of hematocrit values to detect blood manipulations?.  Int J Sports Med. 2000;  21 133-138
• 20 Schumacher Y O, Grathwohl D, Barturen J M, Wollenweber M, Heinrich L, Schmid A, Huber G, Keul J. Haemoglobin, haematocrit and red blood cell indices in elite cyclists.  Are the control values for blood testing valid? Int J Sports Med. 2000;  21 380-385
• 21 Strauss M B, Davies R K, Rosenbaum J D, Rossmeisl E C. Water diuresis produced during recumbency by the intravenous infusion of isotonic saline solution.  J Clin Invest. 1951;  30 862-868
• 22 van Beaumont W. Red cell volume with changes in plasma osmolarity during maximal exercise.  J Appl Physiol. 1973;  35 55-61
• 23 Vergouwen P CJ, Collee T, Marx J JM. Haematocrit in elite athletes.  Int J Sports Med. 1999;  20 538-541
• 24 Wells C L, Stern J R, Kohrt W M, Campbell K D. Fluid shifts with successive running and bicycling performance.  Med Sci Sports Exerc. 1987;  19 137-142
• 25 Whiting P H, Maughan R J, Miller J D. Dehydration and serum biochemical changes in marathon runners.  Eur J Appl Physiol. 1984;  52 183-187
• 26 Wide L, Bengtsson C, Berglund B, Ekbolm B. Detection in blood and urine of recombinant erythropoietin administered to healthy men.  Med Sci Sports Exerc. 1995;  27 1569-1576
• 27 Wilkerson J E, Gutin B, Horvath S M. Exercise-induced changes in blood, red cell, and plasma volumes in man.  Med Sci Sports. 1977;  9 155-158
• 28 Zbigniew S. Erythrocytic system under the influence of physical exercise and training.  Sports Med. 1990;  10 181-197