Plasma Potassium Concentration and Content Changes After Banana Ingestion in Exercised Men

Key Points

Eating up to 2 servings of bananas caused marginal increases in plasma potassium concentration.
The small increases in plasma potassium concentration occurred 30 to 60 minutes postingestion of bananas.
Eating bananas is unlikely to be an effective treatment for exercise-associated muscle cramping.

Department of Health, Nutrition, and Exercise Sciences, North Dakota State University, Fargo

Address correspondence to Kevin C. Miller, PhD, LAT, ATC, Department of Health, Nutrition, and Exercise Sciences, North Dakota State University, PO Box 6050, Department 2620, Fargo, ND 58108. Address e-mail to ude.usdn@relliM.C.niveK.

Abstract

Context

Individuals prone to exercise-associated muscle cramps (EAMCs) are instructed to eat bananas because of their high potassium (K^{) concentration and carbohydrate content and the perception that K}^{imbalances and fatigue contribute to the genesis of EAMCs. No data exist about the effect of bananas on plasma K}^{concentration ([K}^]_p) or plasma glucose concentration ([glucose]_p) after exercise in the heat.

Objective

To determine whether ingesting 0, 1, or 2 servings of bananas after 60 minutes of moderate to vigorous exercise in the heat alters [K^]_p or [glucose]_p and whether changes in [K^]_p result from hypotonic fluid effluxes or K^{ion changes.}

Design

Crossover study.

Setting

Laboratory.

Patients or Other Participants

Nine euhydrated men (age = 27 ± 4 years, height = 180.3 ± 8.4 cm, mass = 84.9 ± 26.1 kg, urine specific gravity ≤ 1.006) without EAMCs volunteered.

Intervention(s)

On 3 separate days, participants completed 60 minutes of moderate to vigorous cycling (temperature = 36.4°C ± 1.1°C, relative humidity = 19.4% ± 2.5%) and then ate 0 g (0 servings), 150 g (1 serving), or 300 g (2 servings) of bananas. Blood samples were collected at −3, 5, 15, 30, and 60 minutes postingestion.

Main Outcome Measure(s)

The [K^]_p, changes in plasma K^{content, plasma volume changes, and [glucose]}_p.

Results

The [K^]_p differed between conditions at 60 minutes; 2 servings (4.6 ± 0.3 mmol/L [conventional unit = 4.6 ± 0.3 mEq/L]) was greater than 1 serving (4.5 ± 0.2 mmol/L [conventional unit = 4.5 ± 0.2 mEq/L]) and 0 servings (4.4 ± 0.3 mmol/L [conventional unit = 4.4 ± 0.3 mEq/L]) (P < .05). The [K^]_p was greater at 60 minutes than at −3 and 5 minutes in the 1-serving condition and was greater at 30 and 60 minutes than at −3 and 5 minutes in the 2-servings condition (P < .05). Percentage change in K^{content was greater only at 30 and 60 minutes postingestion than at baseline in the 2-servings condition (4.4% ± 3.7% and 5.8% ± 2.3% increase, respectively) (}P < .05). The plasma volume changes among conditions were unremarkable. The [glucose]_p was greater in the 2-servings condition than in all other conditions at 15, 30, and 60 minutes (P < .05).

Conclusions

The effect of banana ingestion on EAMCs is unknown; however, these data suggested bananas are unlikely to relieve EAMCs by increasing extracellular [K^{] or [glucose]}_p. The increases in [K^]_p were marginal and within normal clinical values. The changes in [K^]_p, plasma K^{content, and [glucose]}_p do not occur quickly enough to treat acute EAMCs, especially if they develop near the end of competition.

Key Words: electrolytes, fruit, glucose, muscle cramps

Abstract

ACKNOWLEDGMENTS

I thank Mr Jarett Peikert and Mr Kyle Braulick for their assistance with data collection.

ACKNOWLEDGMENTS

REFERENCES

References

1. Norris FH, Jr, Gasteiger EL, Chatfield POAn electromyographic study of induced and spontaneous muscle cramps. Electroencephalogr Clin Neurophysiol. 1956;9(1):139–147.[PubMed]
2. Stone MB, Edwards JE, Stemmans CL, Ingersoll CD, Palmieri-Smith RM, Krause BACertified athletic trainers' perceptions of exercise associated muscle cramps. J Sport Rehabil. 2003;12(4):333–342.[PubMed]
3. Bergeron MFMuscle cramps during exercise: is it fatigue or electrolyte deficit? Curr Sports Med Rep. 2008;7(4 suppl):S50–S55.[PubMed]
4. Bergeron MFHeat cramps: fluid and electrolyte challenges during tennis in the heat. J Sci Med Sport. 2003;6(1):19–27.[PubMed]
5. Stofan JR, Zachwieja JJ, Horswill CA, Murray R, Anderson SA, Eichner ERSweat and sodium losses in NCAA football players: a precursor to heat cramps? Int J Sport Nutr Exerc Metab. 2005;15(6):641–652.[PubMed]
6. Schwellnus MP, Drew N, Collins MMuscle cramping in athletes: risk factors, clinical assessment, and management. Clin Sports Med. 2008;27(1):183–194. ix–x. [[PubMed]
7. Schwellnus MPMuscle cramping in the marathon: aetiology and risk factors. Sports Med. 2007;37(4–5):364–367.[PubMed]
8. Maughan RJExercise induced muscle cramp: a prospective biochemical study in marathon runners. J Sports Sci. 1986;4(1):31–34.[PubMed]
9. Schwellnus MP, Nicol J, Laubscher R, Noakes TDSerum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping (EAMC) in distance runners. Br J Sports Med. 2004;38(4):488–492.
10. Sulzer NU, Schwellnus MP, Noakes TDSerum electrolytes in Ironman triathletes with exercise associated muscle cramping. Med Sci Sports Exerc. 2005;37(7):1081–1085.[PubMed]
11. Medbø JI, Sejersted OMPlasma potassium changes with high intensity exercise. J Physiol. 1990;421:105–122.
12. Vollestad NK, Hallen J, Sejersted OMEffect of exercise intensity on potassium balance in muscle and blood of man. J Physiol. 1994;475(2):359–368.
13. Ettinger PO, Regan TJ, Oldewurtel HAHyperkalemia, cardiac conduction, and the electrocardiogram: a review. Am Heart J. 1974;88(3):360–371.[PubMed]
14. Lindinger MIPotassium regulation during exercise and recovery in humans: implications for skeletal and cardiac muscle. J Mol Cell Cardiol. 1995;27(4):1011–1022.[PubMed]
15. McKenna MJ, Bangsbo J, Renaud JMMuscle K^{, Na}^{, and Cl}^{disturbances and Na}^-K^{pump inactivation: implications for fatigue.}J Appl Physiol. 2008;104(1):288–295.[PubMed]
16. Schwellnus MPCause of exercise associated muscle cramps (EAMC): altered neuromuscular control, dehydration, or electrolyte depletion? Br J Sports Med. 2009;43(6):401–408.[PubMed]
17. American College of Sports Medicine. Sawka MN, Burke LM. et al. American College of Sports Medicine position stand: exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377–390.[PubMed]
18. American College of Sports Medicine. ACSM's Guidelines for Exercise Testing and Prescription. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006. p. 4. [PubMed]
19. Sizer FSS, Whitney EN Nutrition: Concepts and Controversies. 9th ed. Belmont, CA: Thomson Learning Inc; 2003. Appendix A: table of food composition; pp. A1–A87. In. [PubMed]
20. Greenleaf JE, Van Beaumont W, Brock PJ, Morse JT, Mangseth GRPlasma volume and electrolyte shifts with heavy exercise in sitting and supine positions. Am J Physiol. 1979;236(3):R206–R214.[PubMed]
21. Dill DB, Costill DLCalculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. J Appl Physiol. 1974;37(2):247–248.[PubMed]
22. Kristensen M, Juel CPotassium-transporting proteins in skeletal muscle: cellular location and fibre-type differences. Acta Physiol (Oxf)2010;198(2):105–123.[PubMed]
23. Lindinger MI, Grudzien SPExercise-induced changes in plasma composition increase erythrocyte Na^-K^{-ATPase, but not Na}^-K^-2Cl^{cotransporter, activity to stimulate net and unidirectional K}^{transport in humans.}J Physiol. 2003;553(pt 3):987–997.
24. Mitchell JB, Braun WA, Pizza FX, Forrest MPre-exercise carbohydrate and fluid ingestion: influence of glycemic response on 10-km treadmill running performance in the heat. J Sports Med Phys Fitness. 2000;40(1):41–50.[PubMed]
25. Hellmig S, Von Schoning F, Gadow C et alGastric emptying time of fluids and solids in healthy subjects determined by 13C breath tests: influence of age, sex, and body mass index. J Gastroenterol Hepatol. 2006;21(12):1832–1838.[PubMed]
26. Benini L, Castellani G, Brighenti F et alGastric emptying of a solid meal is accelerated by the removal of dietary fibre naturally present in food. Gut. 1995;36(6):825–830.
27. Costill DL, Saltin BFactors limiting gastric emptying during rest and exercise. J Appl Physiol. 1974;37(5):679–683.[PubMed]
28. Manjra S, Schwellnus MP, Noakes TDRisk factors for exercise associated muscle cramping (EAMC) in marathon runners [abstract] Med Sci Sports Exerc. 1996;28(5):S167.[PubMed]
29. Marzio L, Formica P, Fabiani F, LaPenna D, Vecchiett L, Cuccurullo FInfluence of physical activity on gastric emptying of liquids in normal human subjects. Am J Gastroenterol. 1991;86(10):1433–1436.[PubMed]
30. Maughan RJ, Leiper JB, McGaw BAEffects of exercise intensity on absorption of ingested fluids in man. Exp Physiol. 1990;75(3):419–421.[PubMed]
31. Leiper JB, Broad NP, Maughan RJEffect of intermittent high-intensity exercise on gastric emptying in man. Med Sci Sports Exerc. 2001;33(8):1270–1278.[PubMed]
32. Buskirk ER, Puhl SM Body Fluid Balance: Exercise and Sport. Boca Raton, FL: CRC Press; 1996. pp. 19–51. eds. [PubMed]
33. Jeukendrup AECarbohydrate intake during exercise and performance. Nutrition. 2004;20(7–8):669–677.[PubMed]
34. Coggan AR, Coyle EFReversal of fatigue during prolonged exercise by carbohydrate infusion or ingestion. J Appl Physiol. 1987;63(6):2388–2395.[PubMed]
35. Murdoch SD, Bazzarre TL, Snider IP, Goldfarb AHDifferences in the effects of carbohydrate food form on endurance performance to exhaustion. Int J Sport Nutr. 1993;3(1):41–54.[PubMed]
36. Davis JM, Lamb DR, Pate RR, Slentz CA, Burgess WA, Bartoli WPCarbohydrate-electrolyte drinks: effects on endurance cycling in the heat. Am J Clin Nutr. 1988;48(4):1023–1030.[PubMed]
37. Jung A, Bishop P, Al-Nawwas A, Dale RInfluence of hydration and electrolyte supplementation on incidence and time to onset of exercise-associated muscle cramps. J Athl Train. 2005;40(2):71–75.
38. MacIntosh B, Gardiner P, McComas A Skeletal Muscle: Form and Function. 2nd ed. Champaign, IL: Human Kinetics; 2006. Resting and action potentials; pp. 118–136. In. [PubMed]