Renal Function and Plasma Volume Following Ultramarathon Cycling

Abstract

In recreational cyclists marathon cycling influences renal function only on a minimal scale. Respective information on extreme ultramarathon cycling in better trained athletes is not available. The objective was to evaluate the renal and haematological effects of ultraendurance cycling in the world's best ultramarathon cyclists. Creatinine (CR), urea, haemoglobin (Hb), haematocrit (Hct) and plasma volume (PV) were investigated in 16 male ultramarathon cyclists during the 1st Race Across the Alps in 2001 (distance: 525 km; cumulative altitude difference: 12600 m). All renal functional parameters were normal pre-exercise. During the race serum CR, urea and uric acid rose significantly by 33, 97 % and 18 % (p < 0.001 respectively) and nearly normalised again on the following day. The decline in calculated CR clearance was 25 %. There was a negative correlation (r = - 0.575, p = 0.02) between the rise in serum CR and the athlete's training kilometers. The serum urea/CR ratio rose above 40 in 12 athletes (75 %). Mean fractional sodium excretion and fractional uric acid excretion fell below 0.5 % (p < 0.001) and 7 %, indicating reduced renal perfusion. The deflection of the renal functional parameters was temporary and nearly gone after 24 hours of recovery. Hct declined during the race from 0.44 to 0.42, and continued falling on the next day (0.42 → 0.40; p < 0.001). The corresponding rises in calculated PV were + 8 % and + 22 %. The study affirms that in world class cyclists the enormous strains of ultramarathon cycling influence renal function only on a minimal scale. The impact on the PV, however, is pronounced leading to marked haemodilution post-exercise. This very temporary “impairment of renal function” seems to be the physiological response to ultramarathon cycling and may be attenuated to some extent by preceding high-volume training.

Ultramarathon cycling - renal function - renal blood flow - plasma volume expansion - haematocrit

References

• 1 Altenkirch H U, Gerzer R, Kirsch K A, Weil J, Heyduck B, Schultes I, Rocker L. Effect of prolonged physical exercise on fluid regulating hormones.  Eur J Appl Physiol. 1990;  61 209-213
• 2 Armstrong R B. Muscle damage and endurance events.  Sports Med. 1986;  3 370-381
• 3 Castenfors J, Mossfeldt F, Piscator M. Effect of prolonged heavy exercise on renal function and urinary protein excretion.  Acta Physiol Scand. 1967;  70 194-206
• 4 Costill D L. Sweating: its composition and effects on body fluids.  Ann N Y Acad Sci. 1977;  301 160-74
• 5 Dancaster C P, Duckworth W C, Roper C J. Nephropathy in marathon runners.  S Afr Med J. 1969;  43 758-759
• 6 Dancaster C P, Whereat S J. Renal function in marathon runners.  S Afr Med J. 1971;  45 547-551
• 7 Decombaz J, Reinhardt P, Anantharaman K, Von Glutz G, Poortmans J R. Biochemical changes in a 100 km run: free amino acids, urea, and creatinine.  Eur J Appl Physiol. 1979;  41 61-72
• 8 Fallon K E, Sivyer G, Sivyer K, Dare A. The biochemistry of runners in a 1600 km ultramarathon.  Br J Sports Med. 1999;  33 264-269
• 9 Gault M H, Longerich L L, Harnett J D, Wesolowski C. Predicting glomerular function from adjusted serum creatinine (editorial).  Nephron. 1992;  62 249-256
• 10 Green H J, Fraser I G. Differential effects of exercise intensity on serum uric acid concentration.  Med Sci Sports Exerc. 1988;  20 55-59
• 11 Irving R A, Noakes T D, Burger S C, Myburgh K H, Querido D, Van Zyl S R. Plasma volume and renal function during and after ultramarathon running (see comments).  Med Sci Sports Exerc. 1990;  22 581-587
• 12 Irving R A, Noakes T D, Irving G A, Van Zyl S R. The immediate and delayed effects of marathon running on renal function.  J Urol. 1986;  136 1176-1180
• 13 Irving R A, Noakes T D, Raine R I, Van Zyl S R. Transient oliguria with renal tubular dysfunction after a 90 km running race.  Med Sci Sports Exerc. 1990;  22 756-761
• 14 Kreider R B. Physiological considerations of ultraendurance performance.  Int J Sport Nutr. 1991;  1 3-27
• 15 MacSearraigh E TM, Kallmeyer J, Schiff H B. Acute renal failure in marathon runners.  Nephron. 1979;  24 236-240
• 16 Millard R W, Higgins C B, Franklin D, Vatner S F. Regulation of the renal circulation during severe exercise in normal dogs and dogs with experimental heart failure.  Circ Res. 1972;  31 881-888
• 17 Neviackas J A, Bauer J H. Renal function abnormalities induced by marathon running.  South Med J. 1981;  74 1457-1460
• 18 Neumayr G, Pfister R, Hoertnagl H, Mitterbauer G, Getzner W, Ulmer H, Gaenzer H, Joannidis M. The effect of marathon cycling on renal function.  Int J Sports Med. 2003;  24 131-137
• 19 Neumayr G, Pfister R, Mitterbauer G, Gaenzer H, Joannidis M, Eibl G, Hoertnagl H. Short-term effects of prolonged strenuous endurance exercise on the level of haematocrit in amateur cyclists.  Int J Sports Med. 2002;  23 158-161
• 20 Neumayr G, Pfister R, Mitterbauer G, Maurer A, Hoertnagl H. The effect of ultramarathon cycling on the heart rate in elite cyclists.  Br J Sports Med. 2004;  38 55-59
• 21 Ounpuu S. The biomechanics of running: a kinematic and kinetic analysis.  Instr Course Lect. 1990;  39 305-318
• 22 Poortmans J R. Exercise and renal function.  Sports Med. 1984;  1 125-153
• 23 Refsum H E, Stromme S B. Relationship between urine flow, glomerular filtration, and urine solute concentrations during prolonged heavy exercise.  Scand J Clin Lab Invest. 1975;  35 775-780
• 24 Refsum H E, Stromme S B. Renal osmol clearance during prolonged heavy exercise. Scand.  J Clin Lab Invest. 1978;  38 19-22
• 25 Steiner R W. Interpreting the fractional excretion of sodium.  Am J Med. 1984;  77 699-702
• 26 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
• 27 Suzuki M, Sudoh M, Matsubara S, Kawakami K, Shiota M, Ikawa S. Changes in renal blood flow measured by radionuclide angiography following exhausting exercise in humans.  Eur J Appl Physiol. 1996;  74 1-7
• 28 Virvidakis C, Loukas A, Mayopoulou-Symvoulidou M, Mountokalakis T. Renal responses to bicycle exercise in trained athletes: influence of exercise intensity.  Int J Sports Med. 1986;  7 86-88
• 29 West M L, Marsden P A, Richardson R M, Zettle R M, Halperin M L. New clinical approach to evaluate disorders of potassium excretion.  Miner Electrolyte Metab. 1986;  12 234-238
• 30 Williams K R. The relationship between mechanical and physiological energy estimates.  Med Sci Sports Exerc. 1985;  17 317-325