Skip to main content
Log in

Metabolic and circulatory responses to the ingestion of glucose polymer and glucose/electrolyte solutions during exercise in man

  • Published:
European Journal of Applied Physiology and Occupational Physiology Aims and scope Submit manuscript

Summary

Six men exercised on a cycle ergometer for 60 min on two occasions one week apart, at 68±3% of\(\dot V_{{\text{O}}_{{\text{ 2 max}}} } \). On one occasion, a dilute glucose/electrolyte solution (E: osmolality 310 mosmol · kg−1, glucose content 200 mmol·l−1) was given orally at a rate of 100 ml every 10 min, beginning immediately prior to exercise. On the other occasion, a glucose polymer solution (P: osmolality 630 mosmol · kg−1, glucose content equivalent to 916 mmol · l−1) was given at the same rate. Blood samples were obtained from a superficial forearm vein immediately prior to exercise and at 15-min intervals during exercise; further samples were obtained at 15-min intervals for 60 min at rest following exercise. Heart rate and rectal temperature were measured at 5-min intervals during exercise.

Blood glucose concentration was not different between the two tests during exercise, but rose to a peak of 8.7±1.2 mmol · l−1 (mean±SD) at 30 min post-exercise when P was drunk. Blood glucose remained unchanged during and after exercise when E was drunk. Plasma insulin levels were unchanged during exercise and were the same on both trials, but again a sharp rise in plasma insulin concentration was seen after exercise when P was drunk. The rate of carbohydrate oxidation during exercise, as calculated from\(\dot V_{{\text{O}}_{{\text{ 2}}} } \) and the respiratory exchange ratio, was not different between the two tests. A fall in plasma volume, calculated from changes in haematocrit and haemoglobin concentration, occurred after 15 mins of exercise: the fall was of the same magnitude (9%) at this point on both tests, but thereafter plasma volume was significantly lower with P than with E for the remainder of the exercise period and throughout recovery. Serum osmolality increased during exercise (p<0.05) on the P trial, but was unchanged on the E trial. Heart rate was higher (p<0.05) during the last 20 min of exercise on the P trial.

These results suggest that the carbohydrate consumed during the P trial was not available to the working muscles during exercise, and was probably not emptied from the stomach and absorbed to any significant extent until exercise stopped. The differences in plasma volume and osmolality between the two trials are consistent with the net movement of water into the gut which is known to occur at rest when solutions of high osmolality are taken. In more prolonged exercise, this effective dehydration may impair performance.

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

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Ahlborg B, Bergstrom J, Brohult J, Ekelund L-G, Hultman E, Maschio G (1967) Human muscle glycogen content and capacity for prolonged exercise after different diets. Forsvarsmedicin 3:85–99

    Google Scholar 

  • Bergstrom J, Hultman E (1967) A study of the glycogen metabolism during exercise in man. Scand J Clin Lab Invest 19:218–228

    Google Scholar 

  • Bergstrom J, Hermansen L, Hultman E, Saltin B (1967) Diet, muscle glcogen and physical performance. Acta Physiol Scand 71:140–150

    Google Scholar 

  • Boobis LH, Maughan RJ (1983) A simple one-step enzymatic fluorimetric method for the determination of glycerol in 20 μl of plasma. Clin Chim Acta 132:173–180

    Google Scholar 

  • Brewer W, Hendrix TR, McHugh PR (1983) Regulation of the gastric emptying of glucose. Gastroenterology 85:76–82

    Google Scholar 

  • Christensen EH, Hansen O (1939) Arbeitsfähigkeit und Errichtung. Skand Arch Physiol 81:160–171

    Google Scholar 

  • Costill DL (1972) Physiology of marathon running. JAMA 221:1024–1029

    Google Scholar 

  • Costill DL, Saltin B (1974) Factors limiting gastric emptying during rest and exercise. J Appl Physiol 37:679–683

    Google Scholar 

  • Craig FN, Cummings EG (1966) Dehydration and muscular work. J Appl Physiol 21:670–674

    Google Scholar 

  • Dill DB, Costill DL (1974) Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. J Appl Physiol 37:247–248

    Google Scholar 

  • Felig P, Cherif A, Minagawa A, Wahren J (1982) Hypoglycaemia during prolonged exercise in normal man. N Eng J Med 306:895–900

    Google Scholar 

  • Fenn CE, Light IM, Leiper JB, Maughan RJ (1983) Effects of the oral administration of fluid, electrolytes and substrate on endurance capacity in man. J Physiol 341:66P

    Google Scholar 

  • Fordtran JS, Saltin B (1967) Gastric emptying and intestinal absorption during prolonged severe exercise. J Appl Physiol 23:331–335

    Google Scholar 

  • Greenleaf JE, Castle BL (1971) Exercise temperature regulation in man during hypohydration and hyperhydration. J Appl Physiol 30:847–853

    Google Scholar 

  • Hunt JN, Pathak JD (1960) The osmotic effects of some simple molecules and ions on gastric emptying. J Physiol 154:254–269

    Google Scholar 

  • Hunt JN, Spurrell WR (1951) The pattern of emptying of the human stomach. J Physiol 113:157–168

    Google Scholar 

  • Hunt JN, Stubbs DF (1975) The volume and energy content of meals as determinants of gastric emptying. J Physiol 245:209–225

    Google Scholar 

  • Hunt JN, Smith JL, Jiang CL (1985) Effect of meal volume and energy density on the gastric emptying of carbohydrates. Gastroenterology 89:1326–1330

    Google Scholar 

  • Lamb DR, Brodowicz CR (1986) Optimal use of fluids of varying formulations to minimise exercise induced disturbances in homeostasis. Sports Med 3:247–274

    Google Scholar 

  • Leiper JB, Maughan RJ (1986) Absorption of water and electrolytes from hypotonic, isotonic and hypertonic solutions. J Physiol 373:90P

    Google Scholar 

  • Levine SA, Gordon B, Derick CL (1924) Some changes in the chemical constituents of the blood following a marathon race. JAMA 82:1778–1779

    Google Scholar 

  • Maughan RJ (1982) A simple rapid method for the determination of glucose, lactate, pyruvate, alanine, 3-OH butyrate and acetoacetate on a single 20 μl blood sample. Clin Chim Acta 122:232–240

    Google Scholar 

  • Nadel ER, Fortney SM, Wenger CB (1980) Effect of hydration state on circulatory and thermal regulation. J Appl Physiol 49:715–721

    Google Scholar 

  • Olsson K-E, Saltin B (1971) Diet and fluids in training and competition. Scand J Rehab Med 3:31–38

    Google Scholar 

  • Saltin B (1964) Aerobic work capacity and circulation at exercise in man: with special reference to the effect of prolonged exercise and/or heat exposure. Acta Physiol Scand [Suppl 230] 62:1–52

    Google Scholar 

  • Sawka MN, Francesconi RP, Young AJ, Pandolf KB (1984) Influence of hydration level and body fluids on exercise performance in the heat. JAMA 252:1165–1169

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Maughan, R.J., Fenn, C.E., Gleeson, M. et al. Metabolic and circulatory responses to the ingestion of glucose polymer and glucose/electrolyte solutions during exercise in man. Europ. J. Appl. Physiol. 56, 356–362 (1987). https://doi.org/10.1007/BF00690905

Download citation

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00690905

Key words

Navigation