SHEDDING NEW LIGHT ON CARBOHYDRATES AND EXERCISE

Transcription

1 SHEDDING NEW LIGHT ON CARBOHYDRATES AND EXERCISE Dr Javier Gonzalez Department for Health, University of Bath, UK.

2 Van Loon (2012) Energy Stores FAT: >100,000 kcal

3 Van Loon (2012) Energy Stores FAT: >100,000 kcal CHO: <3,200 kcal

4 Oxidation rate (kj/min) Fuels for Exercise Other lipid sources Plasma NEFA Plasma glucose Muscle glycogen (& plasma lactate) Rest Exercise intensity (% W max ) van Loon et al. (2001) J Physiol; Bosch et al. (1994) J Appl Physiol 76(6) Jeukendrup et al. (1999) Am J Phyiol 276(4); Jeukendrup et al. (1999) J Physiol 515(2)

5 Time to fatigue (hours) Muscle Glycogen & Endurance Low CHO Mixed High CHO Muscle glycogen (mmol/kg ww) Bergstrom et al. (1967) Acta Physiol Scand 71: 140

6 Time to fatigue (hours) Muscle Glycogen & Endurance Low CHO Mixed High CHO Muscle glycogen (mmol/kg ww) Bergstrom et al. (1967) Acta Physiol Scand 71: 140

7 Time to fatigue (hours) Muscle Glycogen & Endurance Low CHO Mixed High CHO Muscle glycogen (mmol/kg ww) Bergstrom et al. (1967) Acta Physiol Scand 71: 140

8 What about the Liver? Gonzalez et al. (2016) Am J Physiol 311: E543

9 Coyle et al. (1986) J Appl Physiol 61: 165 Carbohydrate Ingestion Liver

10 Time to fatigue (min) Casey et al. (2000) Am J Physiol Endocrinol Metab 287:E65x Liver Glycogen & Endurance r = 0.53 p < Delta liver glycogen content (g)

11 Nutrition for performance

12 Types of Carbohydrate INTESTINAL LUMEN Glucose SGLT1 INTESTINAL CELLS Glucose GLUT2 BLOODSTREAM

13 Types of Carbohydrate INTESTINAL LUMEN Glucose Glucose Glucose Glucose Glucose Glucose SGLT1 INTESTINAL CELLS Maximum rate ~60 g/h (~1 g/min) Glucose BLOODSTREAM GLUT2

14 Types of Carbohydrate INTESTINAL LUMEN Glucose Fructose SGLT1 GLUT5 INTESTINAL CELLS Maximum rate ~105 g/h (~1.75 g/min) Glucose Fructose GLUT2 GLUT2 BLOODSTREAM

15 Maximizing Carbohydrate Delivery Maximal exogenous CHO oxidation: GLU ~1 g/min GLU + FRU 1.75 g/min SUC = GLU + FRU Liver Jeukendrup (2010) Curr Opin Clin Nutr Metab Care 13(4) Gray & Ingelfinger (1966) J Clin Invest 45(3) Wallis & Wittekind (2013) Int J Sport Nutr Exerc Metab 23(6)

16 But isn t fructose toxic? <5%E Egli et al. (2013) Diabetes 62: 2259

17 But isn t fructose toxic? <5%E 30%E Egli et al. (2013) Diabetes 62: 2259

18 But isn t fructose toxic? Egli et al. (2013) Diabetes 62: 2259 <5%E 30%E 30%E 208 g/d (41 tsp)

19 Participants Age: 25 ± 1 y VO 2 peak: 58 ± 1 ml/min/kg Wpeak: 330 ± 9 W Training volume: 12 ± 2 h/week

20 Study Design

21 Liver Glycogen MRS Scan

22 Muscle Glycogen

23 Study Design GLU or SUC or WAT (1.8 g/min) 600 ml 150 ml MRS Scan Time (min) 180 MRS Scan Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032 = Douglas bag sample

24 Muscle glycogen concentration (mmol/l) Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032 Muscle Glycogen 150 Pre Post WAT (n = 4) GLU (n = 14) SUC (n = 14)

25 Muscle glycogen concentration (mmol/l) Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032 Muscle Glycogen 150 Pre Post WAT (n = 4) GLU (n = 14) SUC (n = 14)

26 Muscle glycogen concentration (mmol/l) Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032 Muscle Glycogen 150 Pre Post WAT (n = 4) GLU (n = 14) SUC (n = 14)

27 Liver glycogen concentration (mmol/l) Liver Glycogen 500 Pre Post WAT (n = 4) GLU (n = 14) SUC (n = 14) Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032

28 Liver glycogen concentration (mmol/l) Liver Glycogen 500 Pre Post WAT (n = 4) GLU (n = 14) SUC (n = 14) Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032

29 Liver glycogen concentration (mmol/l) Liver Glycogen 500 Pre Post WAT (n = 4) GLU (n = 14) SUC (n = 14) Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032

30 Intramyocellular lipid concentration (mmol/g) Intramyocellular Lipid 10 Pre Post No difference in net carbohydrate or fat utilisation in muscle 5 0 WAT (n = 4) Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032 GLU (n = 14) SUC (n = 14)

31 Blood lactate concentration (mmol/l) Blood Lactate GLU SUC Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032 Time (min)

32 Plasma NEFA concentration (mmol/l) Plasma NEFA GLU SUC Time (min)

33 Net substrate utilization (kj) Whole-body Substrate Utilization FAT P = 0.02 FAT CHO P = 0.01 CHO 0 GLU Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032 Trial SUC

34 Gut discomfort 6 Gut Discomfort GLU SUC Sucrose reduces gut Time discomfort P < and RPE Trial NS Interaction P < Gonzalez et al. (2015) Am J Physiol Endocrinol Metab 309(12):E1032 Time (min)

35 Carbohydrates During Exercise When ample CHO (>1 g/min) is provided: Carbohydrate ingestion prevents liver glycogen depletion during endurance exercise Sucrose ingestion increases whole-body carbohydrate utilization during endurance exercise, compared to glucose ingestion

36 Power output (W) What about Performance? 285 a b a PLA Currell & Jeukendrup (2008) Med Sci Sports Exerc GLU GLU + FRU

37 Power output (W) What about Performance? 285 a b a PLA Currell & Jeukendrup (2008) Med Sci Sports Exerc GLU GLU + FRU

38 Power output (W) What about Performance? 285 a b a PLA Currell & Jeukendrup (2008) Med Sci Sports Exerc GLU GLU + FRU

39 CHO during recovery

40 Muscle Glycogen Repletion Betts & Williams (2010) Sports Med 40(11):941.

41 Liver Glycogen Repletion

42 Muscle glycogen concentration (mmol/l) Muscle Glycogen Recovery Glucose Sucrose Fuchs et al. (2016) J Appl Physiol Time (min)

43 Muscle glycogen concentration (mmol/l) Muscle Glycogen Recovery Glucose Sucrose Fuchs et al. (2016) J Appl Physiol Time (min)

44 Muscle glycogen concentration (mmol/l) Muscle Glycogen Recovery Glucose Sucrose Fuchs et al. (2016) J Appl Physiol Time (min)

45 Liver glycogen content (g) Liver Glycogen Recovery Glucose Sucrose # # Fuchs et al. (2016) J Appl Physiol Time (min)

46 Liver glycogen content (g) Liver Glycogen Recovery Glucose Sucrose # # Fuchs et al. (2016) J Appl Physiol Time (min)

47 Liver glycogen content (g) Liver Glycogen Recovery Glucose Sucrose # # Fuchs et al. (2016) J Appl Physiol Time (min)

48 Nausea (AU) Nausea Glucose Sucrose # # Fuchs et al. (2016) J Appl Physiol Time (min)

49 Carbohydrates for Recovery When ample CHO (>1.2 g/kgbm/h) is provided: Glucose-fructose mixtures accelerate liver, but not muscle glycogen repletion rates compared to glucose ingestion only Glucose-fructose mixtures result in less gut discomfort than glucose ingestion only

50 Unresolved questions What is the minimum amount of carbohydrate required to prevent liver glycogen depletion during exercise? What is the optimum amount and type of nutrition for post-exercise liver glycogen recovery? Gonzalez et al. (2016) Am J Physiol 311: E543

51 Summary Carbohydrate ingestion prevents liver glycogen depletion, maintains blood glucose concentration and carbohydrate oxidation Glucose-fructose mixtures increase carbohydrate availability and alleviate gut discomfort during exercise Glucose-fructose mixtures double liver glycogen repletion rates, relative to glucose only, with lower gut discomfort

52 Take Home Messages To maintain optimal endurance performance during prolonged, endurance-type exercise, consider ingesting a mixture of glucose + fructose (sucrose) at a rate of g/h. To accelerate acute post-exercise recovery consider ingesting a mixture of glucose + fructose (sucrose) at a rate of 1.2 g/kgbm/h.

53 Acknowledgements