The Role of Salt and Glucose Replacement Drinks in the Marathon

Abstract

There is a large and growing body of scientific evidence that documents the benefits of ingesting salt and glucose (carbohydrates) during prolonged exercise. Those benefits include maintenance of cardiovascular function, enhanced carbohydrate oxidation, blunted decline in plasma sodium concentration and improved performance. The consumption of ≈1g of carbohydrate per kilogram of bodyweight per hour appears sufficient to improve performance in prolonged exercise. Research also indicates that ≈450mg of sodium per hour is the minimum amount required to maintain plasma volume and slow the decline in plasma sodium concentration that can accompany prolonged exercise in some runners. Adequate carbohydrate and electrolyte intake can be achieved by consuming a well formulated sports drink at regular intervals during exercise, in volumes designed to minimise dehydration. For marathon runners, this could range from ≈400mL to >1.5L per hour, depending upon individual sweating rates.

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References

  1. 1.

    Milvy P, editor. The marathon: physiological, medical, epidenuological, and psychological studies. Ann N Y Acad Sci 1977; 302: 1–1090

    Google Scholar 

  2. 2.

    Maughan RJ. Carbohydrate-electrolyte solutions during prolonged exercise. In: Lamb DR, Williams MH, editors. Perspectives in exercise science and sports medicine: volume 4. Ergogenics: enhancement of performance in exercise and sport. Indianapolis (IN): Brown and Benchmark, 1991: 35–86

    Google Scholar 

  3. 3.

    Gordon B, Kohn LA, Levine SA, et al. Sugar content of the blood in runners following a marathon race. JAMA 1925; 85: 503–4

    Article  Google Scholar 

  4. 4.

    Renbourn ET. The history of sweat and the sweat rash from earliest times to the end of the 18th century. J Hist Med Allied Sci 1959; 14 (2): 20227

    Google Scholar 

  5. 5.

    Talbott JH. Heat cramps. In: Edsell DL, Austin JH, Cobb S, et al., editors. Medicine: analytical review of general medicine, neurology and pediatrics. Baltimore (MD): The Williams and Wilkins Company, 1935: 325–762

    Google Scholar 

  6. 6.

    Levine SA, Gordon B, Derick CL. Some changes in the chenucals consfituents of the blood following a marathon race. JAMA 1924; 82: 1778–9

    Article  CAS  Google Scholar 

  7. 7.

    Hargreaves M. Muscle glycogen and metabolic regulation. Proc Nutr Sac 2004; 63: 217–20

    Article  CAS  Google Scholar 

  8. 8.

    Burke LM, Hawley JA. Eat and carbohydrate for exercise. Curr Opin Clin Nutr Metab Care 2006; 9: 476–81

    PubMed  Article  CAS  Google Scholar 

  9. 9.

    Jentjens RL, Jeukendrup AE. High rates of exogenous carbohydrate oxidation from a mixture of glucose and fructose ingested during prolonged cycling exercise. Br J Nutr 2005; 93: 485–92

    PubMed  Article  CAS  Google Scholar 

  10. 10.

    Jeukendrup AE, Moseley L, Mainwaring GI, et al. Exogenous carbohydrate oxidation during ultra endurance exercise. J Appl Physiol 2006; 100: 1134–41

    PubMed  Article  CAS  Google Scholar 

  11. 11.

    Carter J, Jeukendrup AE, Jones DA. The effect of sweetness on the efficacy of carbohydrate supplementation during exercise in the heat. Can J Appl Physiol 2005; 30: 379–91

    PubMed  Article  Google Scholar 

  12. 12.

    Nose H, Mack GW, Shi X, et al. Role of osmolality and plasma volume during rehydradon in humans. J Appl Physiol 1988; 65: 325–31

    PubMed  CAS  Google Scholar 

  13. 13.

    Passe DH. Physiological and psychological determinants of fluid intake. In: Maughan RJ, Murray R, editors. Sports drinks: basic science and practical aspects. Boca Raton (FL): CRC Press, 2001: 45–88

    Google Scholar 

  14. 14.

    Below PR, Coyle EF. Fluid and carbohydrate ingestion individually benefit intense exercise lasting one hour. Med Sci Sports Exerc 1995; 27: 200–10

    PubMed  CAS  Google Scholar 

  15. 15.

    Vrijens DMJ, Rehrer NJ. Sodium-free fluid ingestion decreases plasma sodium during exercise in the heat. J Appl Physiol 1999; 86: 1847–51

    PubMed  CAS  Google Scholar 

Download references

Acknowledgements

Bob Murray is an employee of The Gatorade Company, a subsidiary of PepsiCo.

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Correspondence to Dr Bob Murray.

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Murray, B. The Role of Salt and Glucose Replacement Drinks in the Marathon. Sports Med 37, 358–360 (2007). https://doi.org/10.2165/00007256-200737040-00021

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Keywords

  • Muscle Glycogen
  • Prolonged Exercise
  • Marathon Runner
  • Carbohydrate Oxidation
  • Sport Drink