Fluid and Electrolyte Balance in Ultra-Endurance Sport

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.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2

References

  1. 1.

    Johnson JM. Regulation of skin circulation during prolonged exercise. Ann N Y Acad Sci 1977; 301: 195–212

    PubMed  Article  CAS  Google 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): 1677–90

    PubMed  Article  CAS  Google 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 press

  4. 4.

    Greenhaff PL, Clough PJ. Predictors of sweat loss in man during prolonged exercise. Eur J Appl Physiol 1989; 58: 348–52

    Article  CAS  Google Scholar 

  5. 5.

    Maughan R. Thermoregulation in marathon competition at low ambient temperature. Int J Sports Med 1985; 6: 15–9

    PubMed  Article  CAS  Google Scholar 

  6. 6.

    Nadel E, Wenger C, Roberts M, et al. Physiological defenses against hyperthermia of exercise. Ann N Y Acad Sci 1977; 301: 98–109

    PubMed  Article  CAS  Google 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): 871–7

    PubMed  CAS  Google Scholar 

  8. 8.

    Montain S, Coyle E. Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise. J Appl Physiol 1992; 73 (4): 1340–50

    PubMed  CAS  Google 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): 895–905

    PubMed  Article  CAS  Google 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): 1032–9

    PubMed  CAS  Google 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): 577–89

    PubMed  Article  CAS  Google 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: 363–6

    PubMed  CAS  Google 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: 1–38

    Google Scholar 

  14. 14.

    Pitts RF. The physiological basis of diuretic therapy. Springfield (IL): C.C. Thomas, 1959

    Google Scholar 

  15. 15.

    Lentner C, editor. Geigy scientific tables. 8th ed. Basel: Ciba-Geigy Ltd., 1981

    Google Scholar 

  16. 16.

    Schmidt RF, Thews G, editors. Human physiology. 2nd ed. Berlin: Springer-Verlag, 1989

    Google Scholar 

  17. 17.

    Maughan RJ. Fluid and electrolyte loss and replacement in exercise. J Sports Sci 1991; 9 (Special): 117–42

    PubMed  Article  Google Scholar 

  18. 18.

    Costill D. Sweating: its composition and effects on body fluids. Ann N Y Acad Sci 1977; 301: 160–74

    PubMed  Article  CAS  Google Scholar 

  19. 19.

    Murray RK, Granner DK, Mayes PA, et al. Harper’s biochemistry. London: Prentice-Hall International Inc., 1988

    Google Scholar 

  20. 20.

    Costill DL, Miller JM. Nutrition for endurance sport. Int J Sports Med 1980; 1: 2–14

    Article  CAS  Google 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): 1847–51

    PubMed  CAS  Google 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): 370–5

    PubMed  CAS  Google Scholar 

  23. 23.

    Frizzell RT, Lang GH, Lowance DC, et al. Hyponatremia and ultramarathon running. JAMA 1986; 255: 772–4

    PubMed  Article  CAS  Google Scholar 

  24. 24.

    Young M, Sciurba F, Rinaldo J. Delirium and pulmonary edema after completing a marathon. Am Rev Respir Dis 1987; 136: 737–9

    PubMed  Article  CAS  Google 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): 234–7

    PubMed  CAS  Google 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): 209–13

    CAS  Google Scholar 

  27. 27.

    Medbo JI, Sejersted OM. Plasma potassium changes with high intensity exercise. J Physiol 1990; 421: 105–22

    PubMed  CAS  Google 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: 1–8

    Article  CAS  Google Scholar 

  29. 29.

    Sjogaard G. Exercise induced potassium fluxes and post-exercise recovery. Int J Sports Med 1989; 10: S99-S100

    Google Scholar 

  30. 30.

    Stansbie D, Tomlinson K, Putman JM, et al. Hypothermia, hypokalaemia and marathon running. Lancet 1982; 2 (8311): 1336

    Google 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: 183–98

    Google 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: 318–25

    Article  CAS  Google 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): 209–15

    PubMed  Article  CAS  Google Scholar 

  34. 34.

    Craig EN, Cummings EG. Dehydration and muscular work. J Appl Physiol 1966; 21 (2): 670–4

    PubMed  CAS  Google Scholar 

  35. 35.

    Nadel ER, Fortney SM, Wenger CB. Effect of hydration state of circulatory and thermal regulations. J Appl Physiol 1980; 49 (4): 715–21

    PubMed  CAS  Google Scholar 

  36. 36.

    Mitchell JW, Nadel ER, Stolwijk JA. Respiratory weight losses during exercise. J Appl Physiol 1972; 32 (4): 474–6

    PubMed  CAS  Google 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): 347–52

    PubMed  CAS  Google 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): 613–8

    PubMed  CAS  Google Scholar 

  39. 39.

    Buskirk E, Beetham Jr W. Dehydration and body temperature as a result of marathon running. Med Sport (Roma) 1960; 14 (9): 493–506

    Google Scholar 

  40. 40.

    International Amateur Athletics Federation (IAAF). Marathon rule. IAAF Rule Book 1953: 65

  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-VII

    PubMed  Article  CAS  Google Scholar 

  42. 42.

    White JA, Ward C, Nelson H. Ergogenic demands of a 24 hour cycling event. Br J Sports Med 1984; 18 (3): 165–71

    PubMed  Article  CAS  Google Scholar 

  43. 43.

    Eden BD, Abernethy PJ. Nutritional intake during an ultraendurance running race. Int J Sport Nutr 1994; 4: 166–74

    PubMed  CAS  Google Scholar 

  44. 44.

    Lindeman AK. Nutrient intake of an ultraendurance cyclist. Int J Sport Nutr 1991; 1: 79–85

    PubMed  CAS  Google 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-S31

    Article  Google Scholar 

  46. 46.

    Kreider RB. Physiological considerations of ultraendurance performance. Int J Sport Nutr 1991; 1: 3–27

    PubMed  CAS  Google 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: 2162–7

    PubMed  CAS  Google 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-S25

    Article  Google 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: 311–9

    Article  CAS  Google Scholar 

  50. 50.

    Sherwood L. Human physiology from cells to systems. Minneapolis (MN): West Publishing Co., 1989

    Google Scholar 

  51. 51.

    Wardlaw GM. Perspectives in nutrition. 4th ed. Boston (MA): McGraw-Hill, 1999

    Google Scholar 

  52. 52.

    Lemon PWR, Mullin JP. Effect of initial muscle glycogen levels on protein catabolism during exercise. J Appl Physiol 1980; 48 (4): 624–9

    PubMed  CAS  Google 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: 121A

    Google Scholar 

  54. 54.

    Mann J, Truswell AS, editors. Essentials of human nutrition. 1st ed. Oxford: Oxford University Press, 1998

    Google Scholar 

  55. 55.

    Newsholme EA, Leech AR. Biochemistry for the medical sciences. Chichester: John Wiley and Sons, 1983

    Google 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): 322–51

    PubMed  Article  CAS  Google 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: 97–127

    Google 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: 1–14

    Google 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): 314–9

    PubMed  CAS  Google 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: 15–9

    CAS  Google Scholar 

  61. 61.

    Fordtran JS, Saltin B. Gastric emptying and intestinal absorption during prolonged severe exercise. J Appl Physiol 1967; 23 (3): 331–5

    PubMed  CAS  Google Scholar 

  62. 62.

    Stephens KR, Rehrer NJ. Gastric emptying during highly intensive, intermittent exercise [abstract]. Med Sci Sports Exerc 1999; 31 Suppl. 5: S324

    Google 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): 673–80

    PubMed  CAS  Google Scholar 

  64. 64.

    Barclay GR, Turnberg LA. Effect of moderate exercise on salt and water transport in the human jejunum. Gut 1988; 29: 816–20

    PubMed  Article  CAS  Google Scholar 

  65. 65.

    Maughan RJ, Leiper JB, McGaw BA. Effects of exercise intensity on absorption of ingested fluid inman. Exp Physiol 1990; 75: 419–21

    PubMed  CAS  Google Scholar 

  66. 66.

    Clausen JP. Effect of physical training on cardiovascular adjustments to exercise in man. Physiol Rev 1977; 57 (4): 779–815

    PubMed  CAS  Google Scholar 

  67. 67.

    Qamar MI, Read AE. Effects of exercise on mesenteric blood flow in man. Gut 1987; 28: 583–7

    PubMed  Article  CAS  Google Scholar 

  68. 68.

    Kenney WL, Ho CW. Age alters regional distribution of blood flow during moderate-intensity exercise. J Appl Physiol 1995; 79 (4): 1112–9

    PubMed  CAS  Google 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): 661–6

    PubMed  Article  CAS  Google 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): 714–8

    PubMed  Article  CAS  Google 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.: S84

    Google 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: 65–79

    PubMed  Article  Google 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: 335–80

    Google 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: 347–424

    Google 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: 123–8

    PubMed  Google 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: 508–14

    PubMed  CAS  Google 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: 1855–60

    PubMed  CAS  Google 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: 247–80

    Google 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: 332–6

    PubMed  CAS  Google 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: 1–8

    Article  CAS  Google Scholar 

  81. 81.

    Wagner DR. Hyperhydrating with glycerol: implications for athletic performance. J Am Diet Assoc 1999; 99: 207–12

    PubMed  Article  CAS  Google 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): 399–406

    PubMed  Article  CAS  Google Scholar 

  83. 83.

    Greenleaf JE, Sargent F. Voluntary dehydration in man. J Appl Physiol 1965; 20: 719–24

    PubMed  CAS  Google 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, 1990

    Google 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: 47–53

    PubMed  CAS  Google 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: 29–52

    PubMed  Article  Google 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: 318–23

    Article  Google Scholar 

Download references

Acknowledgements

The author would like to thank Cardrona Ski Field and Graeme Morgan for the tranquillity in which to research this article and Lance Graham for his clerical assistance.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Nancy J. Rehrer.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Rehrer, N.J. Fluid and Electrolyte Balance in Ultra-Endurance Sport. Sports Med 31, 701–715 (2001). https://doi.org/10.2165/00007256-200131100-00001

Download citation

Keywords

  • Gastric Emptying
  • Atrial Natriuretic Peptide
  • Fluid Loss
  • Sweat Rate
  • Bodyweight Loss