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Nutritional Ergogenic Aids for Endurance Sport.

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Presentation on theme: "Nutritional Ergogenic Aids for Endurance Sport."— Presentation transcript:

1 Nutritional Ergogenic Aids for Endurance Sport


3 Overview Definitions Energy systems and endurance exercise Nutritional ergogenic aids for endurance: Do they work? Summary Ergogenic Aid Research: Improving the Status Quo

4 Definitions Ergogenic = work (performance) enhancing Endurance Exercise = continuous work sustained for 90 – 240 minutes 10 km swim 42 km run 100 km cycle

5 Classification of Ergogenic Aids Pharmacological Examples: anabolic steroids, growth hormone, erythropoietin, diuretics, etc. Mechanical Examples: aerodynamic clothing / helmets, oxygen supplementation, nasal dilators, etc. Nutritional Examples: sports drinks, creatine, chromium, protein powders, etc.

6 Energy Systems

7 Brooks and Mercier, 1994 Energy Systems: Crossover Concept

8 Contribution of Substrates to Energy Expenditure Romijn et al., 1993

9 Glycogen Depletion and Fatigue Bergstrom and Hultman, 1967 Hermansen, 1967; Sherman et al., 1983; Costill et al., km running 80 min cycling 6 x 457 m swimming

10 FAT 8.5 kg 76,500 kcal CHO 0.5 kg 2,000 kcal Milton, FL Miami, FL

11 Nutritional Ergogenic Aids for Endurance Sport Carbohydrate Loading Carnitine Caffeine Ginseng Branched-Chain Amino Acids

12 Carbohydrate Loading Description: One of six classes of nutrients Theory: Primary energy source for exercise above 70% VO 2 max The more glycogen that is stored, the longer fatigue can be delayed in endurance sports

13 Carbohydrate Loading Costill et al., 1985

14 Carbohydrate Loading Fallowfield et al., 1993 * PREPOST AABB

15 Bergstrom et al., 1967  Low CHO Diet  Normal Diet  High CHO Diet Carbohydrate Loading

16 Costill, 1988 Classic, 1967 Modified, 1981 Mod CHO Hi CHO Low CHO Hi CHO

17 Modified Carbohydrate Loading Day 1Day 2Day 3Day 6Day 7Day 4Day 5 MOD CHO DIETHIGH CHO DIET 5g/kg/d8g/kg/d 9 0 min run at 75% VO 2 Endurance Event 40 min run 40 min run 20 min run 20 min run Res t Sherman et al., 1981

18 Sherman, 1988 Carbohydrate Loading

19 Carbohydrate loading improves endurance by ~20% and performance by ~3% (Hawley et al., 1997) An additional 36 min of exercise beyond a 3 hr work effort Current marathon WR is < 3% faster than the WR set in 1969 Khalid Khannouchi, 1999 Chicago Marathon 2:05:42 - WR

20 Carbohydrate Loading Efficacy: 12/12 = 100% Very effective for exercise >70% VO 2 max for more than 90 continuous minutes; dose during “rest phase” of loading is 8 – 10 g/kg/d Safety: Safe at acute therapeutic doses (8- 10g/kg) IOC: Legal

21 Carnitine Description: L-Carnitine is a biologically active, vitamin-like substance produced naturally by the body from two essential amino acids Theory: L-Carnitine is part of a three enzyme complex that facilitates the oxidation of fat More carnitine is speculated to “enhance” this process, thus delaying fatigue in endurance sports


23 Carnitine YES NO  Muscle Tissue Concentration 3 1 (1987 – 1991)  Lipid Oxidation 2 6 (1985 – 1994) Effects of Supplementation

24 Carnitine STUDYPOPULATIONDOSE/DURATIONMEASUREMENTSEFFECT Trappe male athletes4g/d – 7dSwimming performance None Brass “healthy” males 93 mol/kg (IV) at start of exercise RER, VO 2, La, muscle glycogen None Vukovich “healthy” males6g/d – 7-14dRER, FFA, glucose, VO 2, muscle glycogen None Barnett “healthy” males4g/d – 14dLa, muscle carnitine None Colom- bani male athletes4g given before exercise Marathon race performance None

25 Carnitine Efficacy: 5/17 = 29% Very few studies ( ) show any effect of L-Carnitine on physiological or performance variables Safety: L-Carnitine safe at therapeutic doses (2 – 6g) IOC: Legal

26 Caffeine Description: Sometimes considered a pharmacologic ergogenic aid, but is a common constituent of man foods and beverages Theory: Endurance-enhancing potential may stem from caffeine inhibition of phosphodiesterase (increases lipolysis) or by stimulating the adrenal gland and increasing epinephrine (lipolytic hormone) activity

27 Lipolysis HSL (inactive) HSL (active) Adenylyl Cyclase Phospho- diesterase cAMP kinase TG FFA Epinephrine _ Caffeine + _

28 ReferenceDoseEffect Costill et al., mg  21 min endurance Ivy et al., mg  31% FFA oxid. Essig et al., 1980~350 mg42% less glycogen Butts et al., mgNo improvement Sasaki et al., mg  35% endurance Erickson et al., 1987~350 mg30% less glycogen Tarnopolsky et al., 1989~420 mgNo improvement Graham et al., 1991~600 mg55% less glycogen Spriet et al., 1992~650 mg  27% endurance

29 Cheuvront et al., 2009 Quercetin, Caffeine Effects in the heat (40°C)

30 Caffeine Efficacy: 9/11 = 82% Most studies (1978-present) show a positive effect of caffeine on endurance performance (delays muscle glycogen depletion) Safety: Safe at acute therapeutic doses (200 – 1000 mg) IOC Legality* Legal up to 800 mg or 12 mg/L urine – however, doses that enhance performance can be as low as 250 mg!

31 Caffeine Food / BeverageCaffeine (mg) Coffee (180 ml) instant 60 drip 100 brewed / percolated 100 – 150 Tea (180 ml)30 – 40 Cola (360 ml)40 – 50 Chocolate (30 g)10 – 15 Pennington and Church, 1989

32 Ginseng Description: General term for a variety of extracts from the plant family Araliaceae Theory: Active chemical compounds believed to act as adaptogens (increase tolerance to stress), increase O 2 uptake (reduced HR, lactate), and enhance fat oxidation

33 Ginseng Ginsenosides “Chinese Ginseng” 30 Ciwujianosides “Endurox” 13 Eleutherosides “Russian Ginseng” 8

34 Ginseng (Ciwujianosides)

35 Ginseng PLA END Cheuvront et al., %VO 2 max Glycerol (mmol/L) %VO 2 max RER (Ciwujianosides)

36 Ginseng YESNO Ginsenosides (1981 – 2000)4*5 Eleutherosides (1986 – 1996)21 Ciwujianosides (1999)02 * 2 studies used pre-post design; no placebo Effects on Human Exercise Metabolism (all varieties)

37 Ginseng Efficacy: 6/14 = 43% Most well-designed studies show no effect of Ginseng on physiological or performance variables Safety: Safe at therapeutic doses (200 – 2000 mg) IOC Legality Legal* (unless in combination with certain other herbal ingredients)

38 BCAA’s Description: Three essential amino acids (leucine, isoleucine, valine) found naturally in the food supply Theory: Some evidence exists that muscular fatigue originates in the brain (Central Fatigue) and may result from an imbalance in the tryptophan:BCAA

39 Cycling Time (hrs) Plasma Glucose (mmol) Muscle Glycogen (mmol/kg) * ** CHO PLA CHO PLA Cycling Time (hrs) Coyle et al., 1986 Prolonged Exercise and Fatigue

40 Central Fatigue Hypothesis Newsholme et al., 1987 Reduced muscle glycogen and plasma BCAA Increased FFA mobilization Competition for albumin binding Increased fTRP crosses BBB and more 5-HT is made Davis et al., 2000 fTRP5-HT fTRP A A BRAIN CAPILLARY --TRP -- FFA FFA fTRP:BCAA FFA BCAA fTRP BBB fTRP

41 Inhibitory action on cerebral cortex, striatum, and hippocampus Tryptophan Hydroxytryptophan (5-HTP) Serotonin (5-HT) E E CC S H

42 Review of Literature Performance ReferencePhysicalMental Blomstrand et al., 1991No DifferenceImprovement Blomstrand et al., 1991Improvement Varnier et al., 1994No Difference Hassmen, 1994Improvement Van Hall et al., 1995No Difference Blomstrand et al., 1995Improvement Madsen et al., 1996No Difference Blomstrand et al., 1997No DifferenceImprovement Struder et al., 1998No DifferenceImprovement Mittleman et al., 1998ImprovementNo Difference

43 Mittleman et al., 1998 * * * * BCAA Effects in the Heat (35ºC) Exercise

44 Cheuvront et al., 2004 BCAA effects in the heat when hypohydrated

45 BCAA’s Efficacy: 3/10 = 30% (P): 4/5 = 80% (C) Effects on physical performance are equivocal; effects on cognitive performance are more consistent but this may be the result of measurement techniques Safety: Safe at therapeutic doses (7 – 20g) IOC: Legal

46 Bicarbonate Loading Description: Alkaline salt that is part of natural alkaline reserve in body (neutralizes metabolic acids). Also, ingredient in common household baking soda Theory: Since metabolic acidosis is one cause of fatigue during high intensity exercise utilizing the lactic acid energy system, “soda loading” (~300mg/kg or 5-6 tsp baking soda in 1 liter of water) is believed to enhance the buffering capacity of the body and delay fatigue.

47 Bicarbonate: The Evidence Time in 800 meter race under three conditions Time (min:s) SUBJECTCONTROLPLACEBOBICARBONATE 12:09.82:07.02: :05.82:04.52: :03.82:03.32: :00.52:00.41: :00.92:01.61: :14.02:13.72:10.3 Mean2:05.82:05.12:02.9* SEM(s)  2.2  2.0  1.9

48 Bicarbonate Loading Efficacy: Both laboratory and field data support that bicarbonate loading can delay fatigue and enhance performance for sports relying heavily on the lactic acid energy system (running m, swimming m, cycling 3-5 km, even 1-mile run for race horses!). Meta-analysis of the literature (Matson and Tran, 1993) suggests an overall improvement of ~ 25-30% Safety: Generally safe at recommended dosage. GI distress common (nausea, bloating, cramps, diarrhea. At even larger doses, arrhythmias are possible, as is dehydration and muscle spasms. IOC Legality Currently legal.

49 Nutritional Ergogenic Aids: Evidence for Effect on Endurance Performance Carbohydrate Loading Caffeine Bicarbonate Branched-Chain Amino Acids Ginseng Carnitine None

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