Should footballers ingest any carbohydrates at half-time?

By 24 October, 2018Home, Nutrition

At Football Medicine® we always welcome the sharing of relevant knowledge to the sports medicine and science community, reason we challenged the Portuguese nutritionist Fernando Ribeiro to provide an external collaboration to our project, writing a brief article regarding a topic that is often misunderstood in sports nutrition together with our Football Medicine® Sports Nutritionist Vitor Hugo Teixeira.

Fernando Ribeiro (below-left) is graduated in Nutrition by the Faculdade de Ciências da Nutrição e Alimentação da Universidade do Porto – Portugal, being truly engaged on reading and writing sports nutrition topics.

 

 

 

Due to the intermittent nature of football, muscle glycogen is the most important substrate for energy production.(1-3) Actually, glycogen stores fall drastically (from 37 to 90%) during a football match,(4, 5) with almost half of the individual muscle fibers being empty or almost empty at the end of the game.(6) When glycogen levels fall below the amount necessary to maintain a maximum glycolytic rate (~200 mmol/kg dry weight),(6) a decrease in intermittent exercise performance can be observed.(6-8)

The deterioration of technical and physical performances in the 2nd half of a game is well-known, being characterized by a decrease in high intensity running,(9) number of sprints,(6) distance covered,(10) ball possession, ball passes and shots.(11-14) Also, more goals are conceded in the last 15 minutes of a game.(15-17) Strategies for self-adjusting game rhythm can, at least partially, explain the decrease in performance during the second half,(18) but it is more likely that is justified by the cumulative effect of fatigue.(3, 9, 19)

Increasing muscle glycogen levels before exercise, through a carbohydrate-rich diet in the last days before the game, has been shown to delay fatigue and raise performance.(7) Therefore, carbohydrate intake recommendations were set aiming to maximize pre-game muscle glycogen levels.(20) The intake of carbohydrates is also recommended immediately before and during match play to help maintain stable blood glucose concentrations throughout the game.(11, 12, 21, 22) However, evidence has been accumulating that challenges the common notion that high glycemic carbohydrates is the best approach.(11, 21-23)

 

Rebound hypoglycemia – an undesirable reality

 

 

While carbohydrate intake raises glucose levels late in the first half, it does not allow a stable glycaemia throughout the whole game, with a temporary reduction of blood glucose in the first 15 minutes of the second half.(11, 12, 21-23) Hypoglycemia (blood glucose <3.8 mmol/L) occur in approximately 60% of the individuals that consumed carbohydrate-containing beverages within 60 minutes of a simulated football game.(23) Some athletes are remarkably prone to suffer from reactive hypoglycemia,(24) that can be due to the exercise-induced insulin sensitivity.(25-27)

The kinetics of blood glucose response to carbohydrate depend on the time of intake. At rest, the ingestion of carbohydrates raises blood glucose levels, which in turn promotes insulin secretion, that will stimulate the uptake of glucose by the muscle and block the liver glycogenolysis, promoting the normalization of glycaemia.(28) On the contrary, when carbohydrates are ingested during exercise (e.g. in the 1st half), hyperglycemic responses are observed due to the action of cortisol,(29-33) growth hormone(34, 35) and catecholamines, which inhibits insulin release.(35-42)

During half-time, the previous exercise stimulus result in an increase in glucose uptake by skeletal muscle independent of insulin, due to increased expression and translocation of type 4 glucose transporters (GLUT4).(43-45) The intake of high-glycemic carbohydrates during this passive period stimulate insulin release while catecholamine levels have dropped, which may lead to a marked decrease in blood glucose levels at the beginning of the second half of a football game.(4)

There is still no convincing evidence that transient reductions in blood glucose concentrations are associated with reduced performance in athletes.(46, 47) However, and considering that the brain depends primarily on blood glucose for its optimal functioning,(48, 49) it is possible that the decision-making and the performance of specific actions during football matches are affected by blood glucose levels.(50) For example, it was demonstrated that higher blood glucose levels were associated with faster visual discrimination, higher fine motor speed and higher psychomotor speed after a game in the heat.(51)

 

Low-GI carbohydrates at half-time

There is some evidence that the ingestion of low-glycemic carbohydrates reduces the incidence of rebound hypoglycemia.(47, 52) The ingestion of isomaltulose (20g/h) – a low glycemic index carbohydrate (GI= 32), attenuated the decline in blood glucose at the beginning of the 2nd half and maintained higher blood glucose levels in the last 15 minutes of a game, compared to maltodextrin (GI= 90-100).(52) It is important to note that the ingestion of low-glycemic carbohydrates, such as isomaltulose,(53) fructose,(54) galactose or trehalose(47) may increase the prevalence of gastrointestinal disorders, in comparison with glucose or maltodextrin, especially at high doses (>60 g/h).(47, 53) To avoid or minimize the likelihood of gastric perturbations when ingesting low-glycemic carbohydrates, it is recommended to “train the gut”, that benefit gastric emptying, stomach comfort and decrease the perception of fullness.(55) As a general rule, it is also advisable to test the intake during training to evaluate the individual response of each player and implement individualized dietary recommendations.(56, 57)

 

Possible Solutions to Avoid Rebound Hypoglycemia

  1. Prefer low-GI carbohydrates foods for the last meal before game.
  2. Avoid high-glycemic foods in the last hour before game.
  3. Ingest carbohydrates during the warm-up and perform some high-intensity episodes after, to raise catecholamines levels.
  4. Mouth rinse carbohydrates at the beginning of half-time, which improve performance and decline the perception of effort(58-62) without influencing blood glucose and insulin levels.(63)
  5. Ingest carbohydrates only immediately before the start of the 2nd half, when physiological responses are similar to those observed during exercise.

 

Key messages

  • Regarding the intake of carbohydrates, half-time of a football game is a very peculiar moment and may require specific nutritional strategies.
  • The intake of high-glycemic carbohydrates in the half-time can cause rebound hypoglycemia in the first 15 minutes of the 2nd half, which may hinder the performance of the players.
  • The intake of small amounts of low-glycemic carbohydrates, like isomaltulose, during half-time could help maintain a more stable glycaemia throughout the 2nd half.

Authors: Fernando Ribeiro and Vitor Hugo Teixeira

 

References

  1. Bangsbo J. Energy demands in competitive soccer. Journal of sports sciences. 1994; 12 Spec No:S5-12.
  2. Bloomfield J, Polman R, O’Donoghue P. Physical Demands of Different Positions in FA Premier League Soccer. Journal of sports science & medicine. 2007; 6(1):63-70.
  3. Bangsbo J, Mohr M, Krustrup P. Physical and metabolic demands of training and match-play in the elite football player. Journal of sports sciences. 2006; 24(7):665-74.
  4. Bangsbo J, Iaia FM, Krustrup P. Metabolic response and fatigue in soccer. International journal of sports physiology and performance. 2007; 2(2):111-27.
  5. Jacobs I, Westlin N, Karlsson J, Rasmusson M, Houghton B. Muscle glycogen and diet in elite soccer players. European journal of applied physiology and occupational physiology. 1982; 48(3):297-302.
  6. Krustrup P, Mohr M, Steensberg A, Bencke J, Kjaer M, Bangsbo J. Muscle and blood metabolites during a soccer game: implications for sprint performance. Medicine and science in sports and exercise. 2006; 38(6):1165-74.
  7. Balsom PD, Gaitanos GC, Soderlund K, Ekblom B. High-intensity exercise and muscle glycogen availability in humans. Acta physiologica Scandinavica. 1999; 165(4):337-45.
  8. Saltin B. Metabolic fundamentals in exercise. Medicine and science in sports. 1973; 5(3):137-46.
  9. Mohr M, Krustrup P, Bangsbo J. Match performance of high-standard soccer players with special reference to development of fatigue. Journal of sports sciences. 2003; 21(7):519-28.
  10. Barros RML, Misuta MS, Menezes RP, Figueroa PJ, Moura FA, Cunha SA, et al. Analysis of the Distances Covered by First Division Brazilian Soccer Players Obtained with an Automatic Tracking Method. Journal of sports science & medicine. 2007; 6(2):233-42.
  11. Russell M, Benton D, Kingsley M. Influence of carbohydrate supplementation on skill performance during a soccer match simulation. Journal of science and medicine in sport. 2012; 15(4):348-54.
  12. Harper LD, Briggs MA, McNamee G, West DJ, Kilduff LP, Stevenson E, et al. Physiological and performance effects of carbohydrate gels consumed prior to the extra-time period of prolonged simulated soccer match-play. Journal of science and medicine in sport. 2016; 19(6):509-14.
  13. Rampinini E, Impellizzeri FM, Castagna C, Coutts AJ, Wisloff U. Technical performance during soccer matches of the Italian Serie A league: effect of fatigue and competitive level. Journal of science and medicine in sport. 2009; 12(1):227-33.
  14. Russell M, Rees G, Kingsley MI. Technical demands of soccer match play in the English championship. Journal of strength and conditioning research. 2013; 27(10):2869-73.
  15. Yiannakos A, Armatas V. Evaluation of the goal scoring patterns in European Championship in Portugal 2004. International Journal of Performance Analysis in Sport. 2006; 6(1):178-88.
  16. Armatas V, Yiannakos A. Analysis and evaluation of goals scored in 2006 World Cup. Journal of Sport and Health Research. 2010; 2(2):119-28.
  17. Mitrotasios M, Armatas V. Analysis of goal scoring patterns in the 2012 European Football Championship. United States Sports Academy. 2014
  18. Edwards AM, Noakes TD. Dehydration: cause of fatigue or sign of pacing in elite soccer? Sports medicine (Auckland, NZ). 2009; 39(1):1-13.
  19. Mohr M, Krustrup P, Bangsbo J. Fatigue in soccer: a brief review. Journal of sports sciences. 2005; 23(6):593-9.
  20. Oliveira CC, Ferreira D, Caetano C, Granja D, Pinto R, Mendes B, et al. Nutrition and Supplementation in Soccer. Sports (Basel, Switzerland). 2017; 5(2)
  21. Harper LD, Stevenson EJ, Rollo I, Russell M. The influence of a 12% carbohydrate-electrolyte beverage on self-paced soccer-specific exercise performance. Journal of science and medicine in sport. 2017; 20(12):1123-29.
  22. Russell M, Benton D, Kingsley M. Carbohydrate ingestion before and during soccer match play and blood glucose and lactate concentrations. Journal of athletic training. 2014; 49(4):447-53.
  23. Kingsley M, Penas-Ruiz C, Terry C, Russell M. Effects of carbohydrate-hydration strategies on glucose metabolism, sprint performance and hydration during a soccer match simulation in recreational players. Journal of science and medicine in sport. 2014; 17(2):239-43.
  24. Kuipers H, Fransen EJ, Keizer HA. Pre-exercise ingestion of carbohydrate and transient hypoglycemia during exercise. International journal of sports medicine. 1999; 20(4):227-31.
  25. Ebeling P, Bourey R, Koranyi L, Tuominen JA, Groop LC, Henriksson J, et al. Mechanism of enhanced insulin sensitivity in athletes. Increased blood flow, muscle glucose transport protein (GLUT-4) concentration, and glycogen synthase activity. The Journal of clinical investigation. 1993; 92(4):1623-31.
  26. King DS, Dalsky GP, Staten MA, Clutter WE, Van Houten DR, Holloszy JO. Insulin action and secretion in endurance-trained and untrained humans. Journal of applied physiology (Bethesda, Md : 1985). 1987; 63(6):2247-52.
  27. Ryan AS, Muller DC, Elahi D. Sequential hyperglycemic-euglycemic clamp to assess beta-cell and peripheral tissue: studies in female athletes. Journal of applied physiology (Bethesda, Md : 1985). 2001; 91(2):872-81.
  28. Saltiel AR, Kahn CR. Insulin signalling and the regulation of glucose and lipid metabolism. Nature. 2001; 414(6865):799-806.
  29. Hill EE, Zack E, Battaglini C, Viru M, Viru A, Hackney AC. Exercise and circulating cortisol levels: the intensity threshold effect. Journal of endocrinological investigation. 2008; 31(7):587-91.
  30. Clerc D, Wick H, Keller U. Acute cortisol excess results in unimpaired insulin action on lipolysis and branched chain amino acids, but not on glucose kinetics and C-peptide concentrations in man. Metabolism: clinical and experimental. 1986; 35(5):404-10.
  31. Tayek JA, Katz J. Glucose production, recycling, Cori cycle, and gluconeogenesis in humans: relationship to serum cortisol. The American journal of physiology. 1997; 272(3 Pt 1):E476-84.
  32. Khani S, Tayek JA. Cortisol increases gluconeogenesis in humans: its role in the metabolic syndrome. Clinical science (London, England : 1979). 2001; 101(6):739-47.
  33. Keselman B, Vergara M, Nyberg S, Nystrom FH. A randomized cross-over study of the acute effects of running 5 km on glucose, insulin, metabolic rate, cortisol and Troponin T. PLoS One. 2017; 12(6):e0179401.
  34. Moller N, Jorgensen JO, Abildgard N, Orskov L, Schmitz O, Christiansen JS. Effects of growth hormone on glucose metabolism. Hormone research. 1991; 36 Suppl 1:32-5.
  35. Hartley LH. Growth hormone and catecholamine response to exercise in relation to physical training. Medicine and science in sports. 1975; 7(1):34-6.
  36. Sherwin RS, Sacca L. Effect of epinephrine on glucose metabolism in humans: contribution of the liver. The American journal of physiology. 1984; 247(2 Pt 1):E157-65.
  37. Barth E, Albuszies G, Baumgart K, Matejovic M, Wachter U, Vogt J, et al. Glucose metabolism and catecholamines. Critical care medicine. 2007; 35(9 Suppl):S508-18.
  38. Rizza RA, Cryer PE, Haymond MW, Gerich JE. Adrenergic mechanisms of catecholamine action on glucose homeostasis in man. Metabolism: clinical and experimental. 1980; 29(11 Suppl 1):1155-63.
  39. Rassam AG, Martin P, 3rd, Burge MR, Schade DS. The mechanism of glucose-induced catecholamine stimulation. Metabolism: clinical and experimental. 2002; 51(6):761-4.
  40. Watt MJ, Hargreaves M. Effect of epinephrine on glucose disposal during exercise in humans: role of muscle glycogen. American journal of physiology Endocrinology and metabolism. 2002; 283(3):E578-83.
  41. Howlett K, Galbo H, Lorentsen J, Bergeron R, Zimmerman-Belsing T, Bülow J, et al. Effect of adrenaline on glucose kinetics during exercise in adrenalectomised humans. The Journal of Physiology. 1999; 519(Pt 3):911-21.
  42. Mazzeo RS. Catecholamine responses to acute and chronic exercise. Medicine and science in sports and exercise. 1991; 23(7):839-45.
  43. Richter EA, Hargreaves M. Exercise, GLUT4, and skeletal muscle glucose uptake. Physiological reviews. 2013; 93(3):993-1017.
  44. Kennedy JW, Hirshman MF, Gervino EV, Ocel JV, Forse RA, Hoenig SJ, et al. Acute exercise induces GLUT4 translocation in skeletal muscle of normal human subjects and subjects with type 2 diabetes. Diabetes. 1999; 48(5):1192-7.
  45. Messina G, Palmieri F, Monda V, Messina A, Dalia C, De Luca V. Exercise causes muscle GLUT4 translocation in an insulin. Biol Med S. 2015; 3:007.
  46. Hargreaves M, Hawley JA, Jeukendrup A. Pre-exercise carbohydrate and fat ingestion: effects on metabolism and performance. Journal of sports sciences. 2004; 22(1):31-8.
  47. Jentjens RL, Jeukendrup AE. Effects of pre-exercise ingestion of trehalose, galactose and glucose on subsequent metabolism and cycling performance. European journal of applied physiology. 2003; 88(4-5):459-65.
  48. Schonfeld P, Reiser G. Why does brain metabolism not favor burning of fatty acids to provide energy? Reflections on disadvantages of the use of free fatty acids as fuel for brain. Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. 2013; 33(10):1493-9.
  49. Duelli R, Kuschinsky W. Brain glucose transporters: relationship to local energy demand. News in physiological sciences : an international journal of physiology produced jointly by the International Union of Physiological Sciences and the American Physiological Society. 2001; 16:71-6.
  50. Hills SP, Russell M. Carbohydrates for Soccer: A Focus on Skilled Actions and Half-Time Practices. Nutrients. 2018; 10(1):22.
  51. Bandelow S, Maughan R, Shirreffs S, Ozgunen K, Kurdak S, Ersoz G, et al. The effects of exercise, heat, cooling and rehydration strategies on cognitive function in football players. Scandinavian journal of medicine & science in sports. 2010; 20 Suppl 3:148-60.
  52. Stevenson EJ, Watson A, Theis S, Holz A, Harper LD, Russell M. A comparison of isomaltulose versus maltodextrin ingestion during soccer-specific exercise. European journal of applied physiology. 2017; 117(11):2321-33.
  53. Oosthuyse T, Carstens M, Millen AM. Ingesting Isomaltulose Versus Fructose-Maltodextrin During Prolonged Moderate-Heavy Exercise Increases Fat Oxidation but Impairs Gastrointestinal Comfort and Cycling Performance. International journal of sport nutrition and exercise metabolism. 2015; 25(5):427-38.
  54. Fujisawa T, Mulligan K, Wada L, Schumacher L, Riby J, Kretchmer N. The effect of exercise on fructose absorption. The American journal of clinical nutrition. 1993; 58(1):75-9.
  55. Jeukendrup AE. Training the Gut for Athletes. Sports medicine (Auckland, NZ). 2017; 47(Suppl 1):101-10.
  56. Beck KL, Thomson JS, Swift RJ, von Hurst PR. Role of nutrition in performance enhancement and postexercise recovery. Open Access Journal of Sports Medicine. 2015; 6:259-67.
  57. Aragon AA, Schoenfeld BJ, Wildman R, Kleiner S, VanDusseldorp T, Taylor L, et al. International society of sports nutrition position stand: diets and body composition. Journal of the International Society of Sports Nutrition. 2017; 14:16.
  58. Silva TdAe, de Souza MEDCA, de Amorim JF, Stathis CG, Leandro CG, Lima-Silva AE. Can Carbohydrate Mouth Rinse Improve Performance during Exercise? A Systematic Review. Nutrients. 2014; 6(1):1-10.
  59. Carter JM, Jeukendrup AE, Jones DA. The effect of carbohydrate mouth rinse on 1-h cycle time trial performance. Medicine and science in sports and exercise. 2004; 36(12):2107-11.
  60. Beaven CM, Maulder P, Pooley A, Kilduff L, Cook C. Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2013; 38(6):633-7.
  61. Gant N, Stinear CM, Byblow WD. Carbohydrate in the mouth immediately facilitates motor output. Brain research. 2010; 1350:151-8.
  62. Rollo I, Williams C. Effect of mouth-rinsing carbohydrate solutions on endurance performance. Sports medicine (Auckland, NZ). 2011; 41(6):449-61.
  63. Murray KO. Effect of a Carbohydrate Mouth Rinse on Plasma Glucose and Plasma Insulin during a 40-km Cycling Time Trial. The FASEB Journal. 2017; 31(1_supplement):1084.2-84.2.

Tags:

Leave a Reply