Restoration of fluid balance after exercise-induced dehydration: effects of food and fluid intake

  • R. J. Maughan
  • J. B. Leiper
  • S. M. Shirreffs
Original Article

Abstract

This study investigated the effects of post-exercise rehydration with fluid alone or with a meal plus fluid. Eight healthy volunteers (five men, three women) were dehydrated by a mean of 2.1 (SEM 0.0)% of body mass by intermittent cycle exercise in a warm [34 (SEM 0)°C], humid [55 (SEM 1)% relative humidity] environment. Over 60 min beginning 30 min after exercise, the subjects ingested a commercially-available sports drink (21 mmol · l−1 Na+, 3.4 mmol · l K+, 12 mmol · l−1 Cl−1) on trials A and B; on trial C a standard meal [63 kJ · kg−1 body mass (53% CHO, 28%fat,19%protein; 0.118 mmol · kJ−1 Na+, 0.061 mmol · kJ−1 K+)] plus drink (1 mmol · l−1 Na+, 0.4 mmol · l−1 K+, 1 mmol · l−1 Cl) were consumed. Water intake (in millilitres) was 150% of the mass loss (in grams). The trials took place after an overnight fast and were separated by 7 days. Blood and urine samples were collected at intervals throughout the study. Blood was analysed for haematocrit, haemoglobin concentration, serum osmolality, Na+, Ku+ and Cl concentrations and plasma angiotensin II concentration. Urine volume, osmolality and electrolyte concentrations were measured. Dehydration resulted in a mean 5.2 (SEM 1.3)% reduction in plasma volume. With the exception of serum osmolality, which was higher on trial B than A at the end of the rehydration period, no differences were recorded for any of the measured parameters between trials A and B. Cumulative urine output following rehydration was lower (P < 0.01) on trial C [median 665 (range 396–1190) ml] than on trial B [median 934 (range 550–1403) ml] which was not different (P = 0.44) from trial A [median 954 (range 474–1501) ml]. Less urine was produced over the 1-h period ending 2 h after rehydration on trial C than on B (P = 0.01). On trials A and B the subjects were in net negative fluid balance by 337 (range 779-minus 306) ml and 373 (range 680-minus 173) ml, respectively (P < 0.01): on trial C the subjects were no different from their initial euhydrated state [median minus 29 (range minus 421−137) ml] 6 h after the end of rehydration (P = 1.00). A larger fraction of total water intake was retained when the standard meal plus drink was consumed. This may have been due to the larger quantities of Na+ and K+ ingested with the meal [mean 63 (SEM 4)mmol Na+, 21.3 (SEM 1.3)mmol K+] than with the drink [mean 42 (SEM 2) mmol Na+, 6.8 (SEM 0.4) mmol K+]. There was no difference between trials B and C in any of the measured blood parameters, but urinary Na+ and K+ excretion were both higher on trial C than B. These results suggest that post-exercise fluid replacement can be achieved by ingestion of water if consumed in sufficient volume together with a meal providing significant amounts of electrolytes.

Key words

Dehydration Rehydration Fluid balance Electrolyte balance Exercise 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Costill DL, Sparks KE (1973) Rapid fluid replacement following thermal dehydration. J Appl Physiol 34:299–303PubMedGoogle Scholar
  2. Dill DB, Costill DL (1974) Calculation of percentage changes in volumes in blood; plasma and red cells in dehydration. J Appl Physiol 37:247–248PubMedGoogle Scholar
  3. Feig PU, McCurdy DK (1977) The hypertonic state. New Eng J Med 297:1444–1454PubMedCrossRefGoogle Scholar
  4. Gonzalez-Alonso J, Heaps CL, Coyle EF (1992) Rehydration after exercise with common beverages and water. Int J Sports Med 13:399–406PubMedCrossRefGoogle Scholar
  5. Greenleaf JE (1992) Problem: thirst, drinking behavior, and involuntary dehydration. Med Sci Sports Exerc 24:645–656PubMedGoogle Scholar
  6. Lambert CP, Costill DL, McConnell GK, Benedict MA, Lambert GP, Robergs RA, Fink WJ (1992) Fluid replacement after dehydration: influence of beverage carbonation and carbohydrate content. Int J Sports Med 13:285–292PubMedGoogle Scholar
  7. Lentner C (1981) Geigy scientific tables, 8th edn. Ciba-Geigy, BasleGoogle Scholar
  8. Maughan RJ (1991) Carbohydrate-electrolyte solutions during prolonged exercise. In: Lamb DR, Williams MH (eds) Perspectives in exercise science and sports medicine, vol. 4: Brown and Benchmark, Carmel, pp 35–85Google Scholar
  9. Maughan RJ, Leiper JB (1995) Effects of sodium content of ingested fluids on postexercise rehydration in man. Eur J Appl Physiol 71:311–319CrossRefGoogle Scholar
  10. Maughan RJ, Owen JH, Shirreffs SM, Leiper JB (1994) Post-exercise rehydration in man: effects of electrolyte addition to ingested fluids. Eur J Appl Physiol 69:209–215CrossRefGoogle Scholar
  11. Maughan RJ; McArthur M, Shirreffs SM Influence of menstrual status on fluid replacement after exercise-induced dehydration in healthy young women. Br J Sports Med (in press)Google Scholar
  12. Nose H, Mack GW, Shi X, Nadel ER (1988a) Role of osmolality and plasma volume during rehydration in humans. J Appl Physiol 65:325–331PubMedGoogle Scholar
  13. Nose H, Mack GW, ShiX, Nadel ER (1988b) Involvement of sodium retention hormones during rehydration in humans. J Appl Physiol 65:332–336PubMedGoogle Scholar
  14. Paul AA, Southgate DT (1978) McCance and Widdowson's The Composition of Foods, 4th edn. HMSO, LondonGoogle Scholar
  15. Verde T, Shephard RJ, Corey P, Moore R (1982) Sweat composition in exercise and in heat. J Appl Physiol 53:1540–1545PubMedGoogle Scholar

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • R. J. Maughan
    • 1
  • J. B. Leiper
    • 1
  • S. M. Shirreffs
    • 1
  1. 1.University Medical SchoolAberdeenScotland

Personalised recommendations