Sports Medicine

, Volume 31, Issue 10, pp 701–715

Fluid and Electrolyte Balance in Ultra-Endurance Sport

Leading Article

Abstract

It is well known that fluid and electrolyte balance are critical to optimal exercise performance and, moreover, health maintenance. Most research conducted on extreme sporting endeavour (>3 hours) is based on case studies and studies involving small numbers of individuals. Ultra-endurance sportsmen and women typically do not meet their fluid needs during exercise. However, successful athletes exercising over several consecutive days come close to meeting fluid needs. It is important to try to account for all factors influencing bodyweight changes, in addition to fluid loss, and all sources of water input. Increasing ambient temperature and humidity can increase the rate of sweating by up to approximately 1 L/h. Depending on individual variation, exercise type and particularly intensity, sweat rates can vary from extremely low values to more than 3 L/h.

Over-hydration, although not frequently observed, can also present problems, as can inappropriate fluid composition. Over-hydrating or meeting fluid needs during very long-lasting exercise in the heat with low or negligible sodium intake can result in reduced performance and, not infrequently, hyponatraemia. Thus, with large rates of fluid ingestion, even measured just to meet fluid needs, sodium intake is vital and an increased beverage concentration [30 to 50 mmol/L (1.7 to 2.9g NaCl/L) may be beneficial. If insufficient fluids are taken during exercise, sodium is necessary in the recovery period to reduce the urinary output and increase the rate of restoration of fluid balance.

Carbohydrate inclusion in a beverage can affect the net rate of water assimilation and is also important to supplement endogenous reserves as a substrate for exercising muscles during ultra-endurance activity. To enhance water absorption, glucose and/or glucose-containing carbohydrates (e.g. sucrose, maltose) at concentrations of 3 to 5% weight/volume are recommended. Carbohydrate concentrations above this may be advantageous in terms of glucose oxidation and maintaining exercise intensity, but will be of no added advantage and, if hyperosmotic, will actually reduce the net rate of water absorption.

The rate of fluid loss may exceed the capacity of the gastrointestinal tract to assimilate fluids. Gastric emptying, in particular, may be below the rate of fluid loss, and therefore, individual tolerance may dictate the maximum rate of fluid intake. There is large individual variation in gastric emptying rate and tolerance to larger volumes. Training to drink during exercise is recommended and may enhance tolerance.

References

  1. 1.
    Johnson JM. Regulation of skin circulation during prolonged exercise. Ann N Y Acad Sci 1977; 301: 195–212PubMedCrossRefGoogle Scholar
  2. 2.
    Rowell LB, Blackmon JR, Bruce RA. Indocyanine green clearance and estimated hepatic blood flow during mild to maximal exercise in upright man. J Clin Invest 1964; 43 (8): 1677–90PubMedCrossRefGoogle Scholar
  3. 3.
    Rehrer NJ, Smets A, Reynaert H, et al. Effect of exercise on portal vein blood flow in man. Med Sci Sports Exerc. In pressGoogle Scholar
  4. 4.
    Greenhaff PL, Clough PJ. Predictors of sweat loss in man during prolonged exercise. Eur J Appl Physiol 1989; 58: 348–52CrossRefGoogle Scholar
  5. 5.
    Maughan R. Thermoregulation in marathon competition at low ambient temperature. Int J Sports Med 1985; 6: 15–9PubMedCrossRefGoogle Scholar
  6. 6.
    Nadel E, Wenger C, Roberts M, et al. Physiological defenses against hyperthermia of exercise. Ann N Y Acad Sci 1977; 301: 98–109PubMedCrossRefGoogle Scholar
  7. 7.
    Hamilton MT, Gonzalez-Alonso J, Montain SJ, et al. Fluid replacement and glucose infusion during exercise prevent cardiovascular drift. J Appl Physiol 1991; 71 (3): 871–7PubMedGoogle Scholar
  8. 8.
    Montain S, Coyle E. Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise. J Appl Physiol 1992; 73 (4): 1340–50PubMedGoogle Scholar
  9. 9.
    Gonzalez-Alonso J, Calbet AL, Nielsen B. Muscle blood flow is reduced with dehydration during prolonged exercise in humans. J Physiol 1998; 513 (3): 895–905PubMedCrossRefGoogle Scholar
  10. 10.
    Gonzalez-Alonso J, Teller C, Andersen SL, et al. Influence of body temperature on the development of fatigue during prolonged exercise in the heat. J Appl Physiol 1999; 86 (3): 1032–9PubMedGoogle Scholar
  11. 11.
    Gonzalez-Alonso J, Calbet AL, Nielsen B. Metabolic and thermodynamic responses to dehydration-induced reductions in muscle blood flow in exercising humans. J Physiol 1999; 520 (2): 577–89PubMedCrossRefGoogle Scholar
  12. 12.
    Hargreaves M, Dillo P, Angus D, et al. Effect of fluid ingestion on muscle metabolism during prolonged exercise. J Appl Physiol 1996; 80: 363–6PubMedGoogle Scholar
  13. 13.
    Sawka M, Pandolf K. Effects of body water loss on physiological function and exercise performance. In: Gisolfi C, Lamb D, editors. Perspectives in exercise science and sports medicine. Vol. 3. Fluid homeostasis during exercise. Carmel (IN): Benchmark Press Inc., 1990: 1–38Google Scholar
  14. 14.
    Pitts RF. The physiological basis of diuretic therapy. Springfield (IL): C.C. Thomas, 1959Google Scholar
  15. 15.
    Lentner C, editor. Geigy scientific tables. 8th ed. Basel: Ciba-Geigy Ltd., 1981Google Scholar
  16. 16.
    Schmidt RF, Thews G, editors. Human physiology. 2nd ed. Berlin: Springer-Verlag, 1989Google Scholar
  17. 17.
    Maughan RJ. Fluid and electrolyte loss and replacement in exercise. J Sports Sci 1991; 9 (Special): 117–42PubMedCrossRefGoogle Scholar
  18. 18.
    Costill D. Sweating: its composition and effects on body fluids. Ann N Y Acad Sci 1977; 301: 160–74PubMedCrossRefGoogle Scholar
  19. 19.
    Murray RK, Granner DK, Mayes PA, et al. Harper’s biochemistry. London: Prentice-Hall International Inc., 1988Google Scholar
  20. 20.
    Costill DL, Miller JM. Nutrition for endurance sport. Int J Sports Med 1980; 1: 2–14CrossRefGoogle Scholar
  21. 21.
    Vrijens DM, Rehrer NJ. Sodium-free fluid ingestion decreases plasma sodium during exercise in the heat. J Appl Physiol 1999; 86 (6): 1847–51PubMedGoogle Scholar
  22. 22.
    Noakes TD, Goodwin N, Rayner BL, et al. Water intoxication: a possible complication during endurance exercise. Med Sci Sports Exerc 1985; 17 (3): 370–5PubMedGoogle Scholar
  23. 23.
    Frizzell RT, Lang GH, Lowance DC, et al. Hyponatremia and ultramarathon running. JAMA 1986; 255: 772–4PubMedCrossRefGoogle Scholar
  24. 24.
    Young M, Sciurba F, Rinaldo J. Delirium and pulmonary edema after completing a marathon. Am Rev Respir Dis 1987; 136: 737–9PubMedCrossRefGoogle Scholar
  25. 25.
    Garigan T, Ristedt DE. Death from hyponatremia as a result of acute water intoxication in an army basic trainee. Mil Med 1999; 164 (3): 234–7PubMedGoogle Scholar
  26. 26.
    Costill D, Branam G, Fink W, et al. Exercise induced sodium conservation: changes in plasma renin and aldosterone. Med Sci Sports Exerc 1976; 8 (4): 209–13Google Scholar
  27. 27.
    Medbo JI, Sejersted OM. Plasma potassium changes with high intensity exercise. J Physiol 1990; 421: 105–22PubMedGoogle Scholar
  28. 28.
    Rehrer NJ, Brouns F, Beckers EJ, et al. Physiological changes and gastro-intestinal symptoms as a result of ultra-endurance running. Eur J Appl Physiol 1992; 64: 1–8CrossRefGoogle Scholar
  29. 29.
    Sjogaard G. Exercise induced potassium fluxes and post-exercise recovery. Int J Sports Med 1989; 10: S99-S100Google Scholar
  30. 30.
    Stansbie D, Tomlinson K, Putman JM, et al. Hypothermia, hypokalaemia and marathon running. Lancet 1982; 2 (8311): 1336Google Scholar
  31. 31.
    Nadel ER, Mack GW, Nose H. Effects of body water loss on physiological function and exercise performance. In: Gisolfi C, Lamb D, editors. Perspectives in exercise science and sports medicine. Vol. 3. Fluid homeostasis during exercise. Carmel (IN): Benchmark Press, Inc., 1990: 183–98Google Scholar
  32. 32.
    Nielsen B, Sjogaard G, Ugelvig J, et al. Fluid balance in exercise dehydration and rehydration with different glucose-electrolyte drinks. Eur J Appl Physiol 1986; 55: 318–25CrossRefGoogle Scholar
  33. 33.
    Maughan RJ, Owen JH, Shirreffs SM, et al. Post-exercise rehydration in man: effects of electrolyte addition to ingested fluids. Eur J Appl Physiol Occup Physiol 1994; 69 (3): 209–15PubMedCrossRefGoogle Scholar
  34. 34.
    Craig EN, Cummings EG. Dehydration and muscular work. J Appl Physiol 1966; 21 (2): 670–4PubMedGoogle Scholar
  35. 35.
    Nadel ER, Fortney SM, Wenger CB. Effect of hydration state of circulatory and thermal regulations. J Appl Physiol 1980; 49 (4): 715–21PubMedGoogle Scholar
  36. 36.
    Mitchell JW, Nadel ER, Stolwijk JA. Respiratory weight losses during exercise. J Appl Physiol 1972; 32 (4): 474–6PubMedGoogle Scholar
  37. 37.
    Pugh LGCE, Corbett JL, Johnson RH. Rectal temperatures, weight losses, and sweat rates in marathon running. J Appl Physiol 1967; 23 (3): 347–52PubMedGoogle Scholar
  38. 38.
    Pivarnik JM, Leeds EM, Wilkerson JE. Effects of endurance exercise on metabolic water production and plasma volume. J Appl Physiol 1984; 56 (3): 613–8PubMedGoogle Scholar
  39. 39.
    Buskirk E, Beetham Jr W. Dehydration and body temperature as a result of marathon running. Med Sport (Roma) 1960; 14 (9): 493–506Google Scholar
  40. 40.
    International Amateur Athletics Federation (IAAF). Marathon rule. IAAF Rule Book 1953: 65Google Scholar
  41. 41.
    Convertino VA, Armstrong LE, Coyle EF, et al. Position stand on exercise and fluid replacement. Med Sci Sports Exerc 1996; 28 (1): I-VIIPubMedCrossRefGoogle Scholar
  42. 42.
    White JA, Ward C, Nelson H. Ergogenic demands of a 24 hour cycling event. Br J Sports Med 1984; 18 (3): 165–71PubMedCrossRefGoogle Scholar
  43. 43.
    Eden BD, Abernethy PJ. Nutritional intake during an ultraendurance running race. Int J Sport Nutr 1994; 4: 166–74PubMedGoogle Scholar
  44. 44.
    Lindeman AK. Nutrient intake of an ultraendurance cyclist. Int J Sport Nutr 1991; 1: 79–85PubMedGoogle Scholar
  45. 45.
    Saris WHM, Erp-Baart MAV, Brouns F, et al. Study on food intake and energy expenditure during extreme sustained exercise: Tour de France. Int J Sports Med 1989; 10 Suppl. 1: S26-S31CrossRefGoogle Scholar
  46. 46.
    Kreider RB. Physiological considerations of ultraendurance performance. Int J Sport Nutr 1991; 1: 3–27PubMedGoogle Scholar
  47. 47.
    Westerterp KR, Saris WHM, Van ME, et al. Use of doubly labeled water technique in humans during heavy sustained exercise. J Appl Physiol 1986; 61: 2162–7PubMedGoogle Scholar
  48. 48.
    Rehrer NJ, Janssen GME, Brouns F, et al. Fluid intake and gastrointestinal problems in runners competing in a 25-km race and a marathon. Int J Sports Nutr 1989; 10 Suppl. 1: S22-S25CrossRefGoogle Scholar
  49. 49.
    Maughan RJ, Leiper JB. Effects of sodium content of ingested fluids on post-exercise rehydration in man. Eur J Appl Physiol 1995; 71: 311–9CrossRefGoogle Scholar
  50. 50.
    Sherwood L. Human physiology from cells to systems. Minneapolis (MN): West Publishing Co., 1989Google Scholar
  51. 51.
    Wardlaw GM. Perspectives in nutrition. 4th ed. Boston (MA): McGraw-Hill, 1999Google Scholar
  52. 52.
    Lemon PWR, Mullin JP. Effect of initial muscle glycogen levels on protein catabolism during exercise. J Appl Physiol 1980; 48 (4): 624–9PubMedGoogle Scholar
  53. 53.
    Leiper J, Fenn C, Maughan R. The effect of diet and prolonged walking on fluid homeostasis [abstract]. Proc Nutr Soc 1988; 47: 121AGoogle Scholar
  54. 54.
    Mann J, Truswell AS, editors. Essentials of human nutrition. 1st ed. Oxford: Oxford University Press, 1998Google Scholar
  55. 55.
    Newsholme EA, Leech AR. Biochemistry for the medical sciences. Chichester: John Wiley and Sons, 1983Google Scholar
  56. 56.
    Murray R. The effects of consuming carbohydrate-electrolyte beverages on gastric emptying and fluid absorption during and following exercise. Sports Med 1987; 4 (5): 322–51PubMedCrossRefGoogle Scholar
  57. 57.
    Costill DL. Gastric emptying of fluids during exercise. In: Gisolfi CV, Lamb DR, editors. Perspectives in exercise science and sports medicine. Vol. 3. Fluid homeostasis during exercise. Carmel (IN): Benchmark Press, 1990: 97–127Google Scholar
  58. 58.
    Rehrer NJ, Brouns F, Beckers EJ, et al. The influence of beverage composition and gastrointestinal function on fluid and nutrient availability during exercise. Scand J Med Sci Sports 1994; 4: 1–14Google Scholar
  59. 59.
    Mitchell JB, Voss KW. The influence of volume on gastric emptying and fluid balance during prolonged exercise. Med Sci Sports Exerc 1991; 23 (3): 314–9PubMedGoogle Scholar
  60. 60.
    Cunningham KM, Horowitz M, Read NW. The effect of shortterm dietary supplementation with glucose on gastric emptying in humans. Br J Sports Med 1991; 65: 15–9Google Scholar
  61. 61.
    Fordtran JS, Saltin B. Gastric emptying and intestinal absorption during prolonged severe exercise. J Appl Physiol 1967; 23 (3): 331–5PubMedGoogle Scholar
  62. 62.
    Stephens KR, Rehrer NJ. Gastric emptying during highly intensive, intermittent exercise [abstract]. Med Sci Sports Exerc 1999; 31 Suppl. 5: S324Google Scholar
  63. 63.
    Yamaji R, Sakamoto M, Miyatake K, et al. Hypoxia inhibits gastric emptying and gastric acid secretion in conscious rats. J Nutr 1996; 126 (3): 673–80PubMedGoogle Scholar
  64. 64.
    Barclay GR, Turnberg LA. Effect of moderate exercise on salt and water transport in the human jejunum. Gut 1988; 29: 816–20PubMedCrossRefGoogle Scholar
  65. 65.
    Maughan RJ, Leiper JB, McGaw BA. Effects of exercise intensity on absorption of ingested fluid inman. Exp Physiol 1990; 75: 419–21PubMedGoogle Scholar
  66. 66.
    Clausen JP. Effect of physical training on cardiovascular adjustments to exercise in man. Physiol Rev 1977; 57 (4): 779–815PubMedGoogle Scholar
  67. 67.
    Qamar MI, Read AE. Effects of exercise on mesenteric blood flow in man. Gut 1987; 28: 583–7PubMedCrossRefGoogle Scholar
  68. 68.
    Kenney WL, Ho CW. Age alters regional distribution of blood flow during moderate-intensity exercise. J Appl Physiol 1995; 79 (4): 1112–9PubMedGoogle Scholar
  69. 69.
    Seto H, Kageyama M, Nomura K, et al. Whole-body 201Tl scintigraphy during one-leg exercise and at rest in normal subjects: estimation of regional blood flow changes. Nucl Med Commun 1995; 16 (8): 661–6PubMedCrossRefGoogle Scholar
  70. 70.
    Sabba C, Ferraioli G, Genecin P, et al. Evaluation of postprandial hyperemia in superior mesenteric artery and portal vein in healthy and cirrhotic humans: an operator-blind echo- Doppler study. Hepatology 1991; 13 (4): 714–8PubMedCrossRefGoogle Scholar
  71. 71.
    Rehrer NJ, Goes E, DuGgardeyn C, et al. Effects of carbohydrate and fluid ingestion on splanchnic blood flow at rest and during exercise [abstract]. Med Sci Sports Exerc 1993; 25 Suppl.: S84Google Scholar
  72. 72.
    Leiper JB, Maughan RJ. Experimental models for the investigation of water and solute transport in man: implications for oral rehydration solutions. Drugs 1988; 36 Suppl. 4: 65–79PubMedCrossRefGoogle Scholar
  73. 73.
    Ryan AJ. Heat stroke and endotoxemia: sensitization or tolerance to endotoxins? In: Gisolfi CV, Lamb DR, Nadel ER, editors. Exercise, heat and thermoregulation. Dubuque (IA): Wm. C. Brown Publishers, 1993: 335–80Google Scholar
  74. 74.
    Johnson AK. Brain mechanisms in the control of body fluid homeostasis. In: Gisolfi CV, Lamb DR, editors. Perspectives in exercise science and sports medicine. Vol. 3. Fluid homeostasis during exercise. Carmel (IN): Benchmark Press, 1990: 347–424Google Scholar
  75. 75.
    Convertino V, Keil L, Bernaver E, et al. Plasma volume, osmolarity, vasopressin and renin activity during graded exercise in man. J Appl Physiol 1981; 50: 123–8PubMedGoogle Scholar
  76. 76.
    Convertino V, Keil L, Greenleaf JE. Plasma volume, renin and vasopressin responses to graded exercise after training. J Appl Physiol 1983; 54: 508–14PubMedGoogle Scholar
  77. 77.
    Francesconi R, Sawka M, Pandolf K, et al. Plasma hormonal responses at graded hypohydration levels during exercise heat stress. J Appl Physiol 1985; 59: 1855–60PubMedGoogle Scholar
  78. 78.
    Zambraski EJ. Renal regulation of fluid homeostasis during exercise. In: Gisolfi CV, Lamb DR, editors. Perspectives in exercise science and sports medicine. Vol. 3. Fluid homeostasis during exercise. Carmel (IN): Benchmark Press, 1990: 247–80Google Scholar
  79. 79.
    Nose H, Mack GW, Shi X, et al. Involvement of sodium retention hormones during rehydration in humans. J Appl Physiol 1988; 65: 332–6PubMedGoogle Scholar
  80. 80.
    Jimenez C, Melin B, Koulmann N, et al. Plasma volume changes during and after acute variations of body hydration level in human. Eur J Appl Physiol 1999; 80: 1–8CrossRefGoogle Scholar
  81. 81.
    Wagner DR. Hyperhydrating with glycerol: implications for athletic performance. J Am Diet Assoc 1999; 99: 207–12PubMedCrossRefGoogle Scholar
  82. 82.
    Gonzalez-Alonso J, Heaps C, Coyle E. Rehydration after exercise with common beverages and water. Int J Sports Med 1992; 13 (5): 399–406PubMedCrossRefGoogle Scholar
  83. 83.
    Greenleaf JE, Sargent F. Voluntary dehydration in man. J Appl Physiol 1965; 20: 719–24PubMedGoogle Scholar
  84. 84.
    Hubbard RW, Szlyz PC, Armstrong LE. Influence of thirst and fluid palatability on fluid ingestion during exercise. In: Gisolfi CV, Lamb DR, editors. Perspectives in exercise science and sports medicine. Vol. 3. Fluid homeostasis during exercise. Carmel (IN): Benchmark Press, 1990Google Scholar
  85. 85.
    Kovacs EMR, Senden JMG, Brouns F. Urine color, osmolality and specific electrical conductance are not accurate measures of hydration status during postexercise rehydration. J Sports Med Phys Fitness 1999; 39: 47–53PubMedGoogle Scholar
  86. 86.
    Coyle EF. Timing and method of increased carbohydrate intake to cope with heavy training, competition and recovery. J Sports Sci 1991; 9: 29–52PubMedCrossRefGoogle Scholar
  87. 87.
    Saunders B, Noakes TD, Dennis SC. Water and electrolyte shifts with partial fluid replacement during exercise. Eur J Appl Physiol 1999; 80: 318–23CrossRefGoogle Scholar

Copyright information

© Adis International Limited 2001

Authors and Affiliations

  1. 1.School of Physical Education and Department of Human NutritionOtago UniversityDunedinNew Zealand

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