Carbohydrate consumption and variable-intensity exercise responses in boys and men

  • Lisa M. Guth
  • Michael P. Rogowski
  • Justin P. Guilkey
  • Anthony D. MahonEmail author
Original Article



The effect of carbohydrate (CHO) supplementation on physiological and perceptual responses to steady-state exercise has been studied in children. However, little is known about these responses to variable-intensity exercise (VIE) and how these responses might differ from adults. This study examined the physiological and perceptual effects of CHO on VIE in boys and men.


Eight boys (11.1 ± 0.9 years) and 11 men (23.8 ± 2.1 years) consumed CHO or a placebo (PL) beverage before and throughout VIE (three 12-min cycling bouts with intensity varying every 20–30 s between 25, 50, 75, and 125% peak work rate). Pulmonary gas exchange was assessed during the second 12-min bout. RPE was assessed twice per bout.


In CHO, blood glucose increased and then decreased more from pre-exercise to 12 min and was higher in this trial at the end of exercise in men versus boys. In boys, blood glucose in CHO was higher at 24 and 36 min of exercise than in PL. RER during the CHO trial was higher in both groups; the other physiological responses were unaffected by CHO. All RPE measures (whole body, legs and chest) increased over time, but were not different between groups or trials.


Blood glucose patterns during VIE were differentially affected by CHO in boys and men, but most physiological and perceptual responses to VIE were unaffected by CHO in either group. Knowledge of the underlying mechanisms of glucose regulation and effects on physical performance during this type of exercise in children is warranted.


Blood glucose Metabolism Child–adult difference Cycle ergometry 



Analysis of variance




Heart rate


Loughborough Intermittent Shuttle Test




Respiratory exchange ratio


Rating of perceived exertion


Variable-intensity exercise


Oxygen uptake


Author contributions

LMG and ADM developed the study, participated in the data collection and analysis, and are the paper’s primary authors. MPR and JPG assisted with some of the data collection and reviewed drafts of the paper prior to submission.


This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Compliance with ethical standards

Conflict of interest

None of the authors declare competing financial interests.


  1. Ahlborg G, Felig P (1976) Influence of glucose ingestion on fuel-hormone response during prolonged exercise. J Appl Physiol 41(5 Pt. 1):683–688CrossRefGoogle Scholar
  2. Ali A, Williams C, Nicholas CW, Foskett A (2007) The influence of carbohydrate–electrolyte ingestion on soccer skill performance. Med Sci Sports Exerc 39(11):1969–1976. CrossRefGoogle Scholar
  3. Aucouturier J, Baker JS, Duche P (2008) Fat and carbohydrate metabolism during submaximal exercise in children. Sports Med 38(3):213–238CrossRefGoogle Scholar
  4. Bar-Or O, Ward DS (1989) Rating of perceived exertion in children. In: Bar-Or O (ed) Advances in pediatric sports sciences, vol 3. Human Kinetics Publishers, Champaign, pp 151–168Google Scholar
  5. Burgess ML, Robertson RJ, Davis JM, Norris JM (1991) RPE, blood glucose, and carbohydrate oxidation during exercise: effects of glucose feedings. Med Sci Sports Exerc 23(3):353–359CrossRefGoogle Scholar
  6. Cheatham CC, Mahon AD, Brown JD, Bolster DR (2000) Cardiovascular responses during prolonged exercise at ventilatory threshold in boys and men. Med Sci Sports Exerc 32(6):1080–1087CrossRefGoogle Scholar
  7. Davis JM, Jackson DA, Broadwell MS, Queary JL, Lambert CL (1997) Carbohydrate drinks delay fatigue during intermittent, high-intensity cycling in active men and women. Int J Sport Nutr 7(4):261–273CrossRefGoogle Scholar
  8. de Sousa MV, Simoes HG, Oshiiwa M, Rogero MM, Tirapegui J (2007) Effects of acute carbohydrate supplementation during sessions of high-intensity intermittent exercise. Eur J Appl Physiol 99(1):57–63. CrossRefGoogle Scholar
  9. Delamarche P, Monnier M, Gratas-Delamarche A, Koubi HE, Mayet MH, Favier R (1992) Glucose and free fatty acid utilization during prolonged exercise in prepubertal boys in relation to catecholamine responses. Eur J Appl Physiol Occup Physiol 65(1):66–72CrossRefGoogle Scholar
  10. Delamarche P, Gratas-Delamarche A, Monnier M, Mayet MH, Koubi HE, Favier R (1994) Glucoregulation and hormonal changes during prolonged exercise in boys and girls. Eur J Appl Physiol Occup Physiol 68(1):3–8CrossRefGoogle Scholar
  11. Eriksson BO (1972) Physical training, oxygen supply and muscle metabolism in 11-13-year old boys. Acta Physiol Scand Suppl 384:1–48Google Scholar
  12. Eriksson O, Saltin B (1974) Muscle metabolism during exercise in boys aged 11 to 16 years compared to adults. Acta Paediatr Belgica Suppl 28:257–265Google Scholar
  13. Eriksson BO, Gollnick PD, Saltin B (1973) Muscle metabolism and enzyme activities after training in boys 11–13 years old. Acta Physiol Scand 87(4):485–497. CrossRefGoogle Scholar
  14. Foricher JM, Boisseau N, Ville NS, Berthon PM, Bentue-Ferrer D, Gratas-Delamarche A, Delamarche P (2003) Effects of an oral glucose challenge on metabolic and hormonal responses to exercise in active prepubertal girls. Pediatr Exerc Sci 15(3):266–276CrossRefGoogle Scholar
  15. Foskett A, Williams C, Boobis L, Tsintzas K (2008) Carbohydrate availability and muscle energy metabolism during intermittent running. Med Sci Sports Exerc 40:96–103. CrossRefGoogle Scholar
  16. Gaesser GA, Poole DC (1996) The slow component of oxygen uptake kinetics in humans. Exerc Sport Sci Rev 24:35–71CrossRefGoogle Scholar
  17. Loftin M, Sothern M, Abe T, Bonis M (2016) Expression of VO2peak in children and youth, with special reference to allometric scaling. Sports Med 46(10):1451–1460. CrossRefGoogle Scholar
  18. Maes BD, Ghoos YF, Geypens BJ, Hiele MI, Rutgeerts PJ (1995) Relation between gastric emptying rate and energy intake in children compared with adults. Gut 36(2):183–188CrossRefGoogle Scholar
  19. Mahon AD, Timmons BW (2014) Application of stable isotope tracers in the study of exercise metabolism in children: a primer. Pediatr Exerc Sci 26(1):3–10. CrossRefGoogle Scholar
  20. Mahon AD, Stolen KQ, Gay JA (2001) Differentiated perceived exertion during submaximal exercise in children and adults. Pediatr Exerc Sci 13:145–153CrossRefGoogle Scholar
  21. Mahon AD, Guth LM, Kraft KA (2010) Physiological and perceptual responses in children during variable-intensity exercise. In: Baquet G, Berthoin S (eds) Children and exercise XXV. Routledge, London, pp 171–177Google Scholar
  22. Martinez LR, Haymes EM (1992) Substrate utilization during treadmill running in prepubertal girls and women. Med Sci Sports Exerc 24(9):975–983CrossRefGoogle Scholar
  23. Nicholas CW, Williams C, Lakomy HK, Phillips G, Nowitz A (1995) Influence of ingesting a carbohydrate-electrolyte solution on endurance capacity during intermittent, high-intensity shuttle running. J Sports Sci 13(4):283–290CrossRefGoogle Scholar
  24. Noble BJ, Robertson RJ (1996) Perceived exertion. Human Kinetics, ChampaignGoogle Scholar
  25. Oseid S, Hermansen L (1971) Hormonal and metabolic changes during and after prolonged muscular work in pre-pubertal boys. Acta Paediatr Scand Suppl 217:147–153CrossRefGoogle Scholar
  26. Passonneau JV, Lowry OH (1993) Enzymatic analysis: a practical guide. Biological methods. Humana Press, TotowaCrossRefGoogle Scholar
  27. Phillips SM, Turner AP, Gray S, Sanderson MF, Sproule J (2010) Ingesting a 6% carbohydrate-electrolyte solution improves endurance capacity, but not sprint performance, during intermittent, high-intensity shuttle running in adolescent team games players aged 12–14 years. Eur J Appl Physiol 109(5):811–821. CrossRefGoogle Scholar
  28. Phillips SM, Turner AP, Sanderson MF, Sproule J (2012) Carbohydrate gel ingestion significantly improves the intermittent endurance capacity, but not sprint performance, of adolescent team games players during a simulated team games protocol. Eur J Appl Physiol 112(3):1133–1141. CrossRefGoogle Scholar
  29. Ratel S, Williams CA, Oliver J, Armstrong N (2004) Effects of age and mode of exercise on power output profiles during repeated sprints. Eur J Appl Physiol 92(1–2):204–210. CrossRefGoogle Scholar
  30. Riddell MC (2008) The endocrine response and substrate utilization during exercise in children and adolescents. J Appl Physiol 105(2):725–733. CrossRefGoogle Scholar
  31. Riddell MC, Bar-Or O, Schwarcz HP, Heigenhauser GJ (2000) Substrate utilization in boys during exercise with [13C]-glucose ingestion. Eur J Appl Physiol 83(4–5):441–448CrossRefGoogle Scholar
  32. Riddell MC, Bar-Or O, Wilk B, Parolin ML, Heigenhauser GJ (2001) Substrate utilization during exercise with glucose and glucose plus fructose ingestion in boys ages 10–14 year. J Appl Physiol 90(3):903–911CrossRefGoogle Scholar
  33. Robertson RJ, Goss FL, Boer NF, Peoples JA, Foreman AJ, Dabayebeh IM, Millich NB, Balasekaran G, Riechman SE, Gallagher JD, Thompkins T (2000) Children’s OMNI scale of perceived exertion: mixed gender and race validation. Med Sci Sports Exerc 32(2):452–458CrossRefGoogle Scholar
  34. Snyder AC, Moorhead K, Luedtke J, Small M (1993) Carbohydrate consumption prior to repeated bouts of high-intensity exercise. Eur J Appl Physiol Occup Physiol 66(2):141–145CrossRefGoogle Scholar
  35. Stephens BR, Cole AS, Mahon AD (2006) The influence of biological maturation on fat and carbohydrate metabolism during exercise in males. Int J Sport Nutr Exerc Metab 16(2):166–179CrossRefGoogle Scholar
  36. Stevens J (2002) Applied multivariate statistics for the social sciences. Lawrence Erlbaum Associates, MahwahGoogle Scholar
  37. Tanner JM (1962) Growth at adolescence, with a general consideration of the effects of hereditary and environmental factors upon growth and maturation from birth to maturity, 2d edn. Blackwell Scientific Publications, OxfordGoogle Scholar
  38. Timmons BW, Bar-Or O (2003) RPE during prolonged cycling with and without carbohydrate ingestion in boys and men. Med Sci Sports Exerc 35(11):1901–1907CrossRefGoogle Scholar
  39. Timmons BW, Bar-Or O, Riddell MC (2003) Oxidation rate of exogenous carbohydrate during exercise is higher in boys than in men. J Appl Physiol 94(1):278–284CrossRefGoogle Scholar
  40. Timmons BW, Bar-Or O, Riddell MC (2007a) Energy substrate utilization during prolonged exercise with and without carbohydrate intake in preadolescent and adolescent girls. J Appl Physiol 103(3):995–1000CrossRefGoogle Scholar
  41. Timmons BW, Bar-Or O, Riddell MC (2007b) Influence of age and pubertal status on substrate utilization during exercise with and without carbohydrate intake in healthy boys. Appl Physiol Nutr Metab 32(3):416–425CrossRefGoogle Scholar
  42. Utter AC, Kang J, Nieman DC, Dumke CL, McAnulty SR, McAnulty LS (2007) Carbohydrate attenuates perceived exertion during intermittent exercise and recovery. Med Sci Sports Exerc 39(5):880–885. CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Human Performance LaboratoryBall State UniversityMuncieUSA
  2. 2.Department of KinesiologyCoastal Carolina UniversityConwayUSA

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