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Nutritional Ergogenic Aids for Endurance Sport

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  1. Nutritional Ergogenic Aids for Endurance Sport

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

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

  4. 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.

  5. Energy Systems

  6. Energy Systems:Crossover Concept Brooks and Mercier, 1994

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

  8. 6 x 457 m swimming 42 km running 80 min cycling Hermansen, 1967; Sherman et al., 1983; Costill et al., 1988 Glycogen Depletion and Fatigue Bergstrom and Hultman, 1967

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

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

  11. Carbohydrate Loading • Description: One of six classes of nutrients • Theory: Primary energy source for exercise above 70% VO2max The more glycogen that is stored, the longer fatigue can be delayed in endurance sports

  12. Carbohydrate Loading Costill et al., 1985

  13. Carbohydrate Loading * A B A B PRE POST Fallowfield et al., 1993

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

  15. Carbohydrate Loading Mod CHO Hi CHO Low CHO Hi CHO Modified, 1981 Classic, 1967 Costill, 1988

  16. Modified Carbohydrate Loading Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 MOD CHO DIET HIGH CHO DIET 5g/kg/d 8g/kg/d 90 min run at 75% VO2 Endurance Event 40 min run 40 min run 20 min run 20 min run Rest Sherman et al., 1981

  17. Carbohydrate Loading 9.0 7.0 5.0 2.5 Sherman, 1988

  18. Carbohydrate Loading • 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

  19. Carbohydrate Loading • Efficacy: 12/12 = 100% Very effective for exercise >70% VO2max 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

  20. 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

  21. 1 4 2 3

  22. Carnitine Effects of Supplementation YES NO  Muscle Tissue Concentration 3 1 (1987 – 1991)  Lipid Oxidation2 6 (1985 – 1994)

  23. Carnitine

  24. Carnitine • Efficacy: 5/17 = 29% Very few studies (1985-1996) show any effect of L-Carnitine on physiological or performance variables • Safety: L-Carnitine safe at therapeutic doses (2 – 6g) • IOC: Legal

  25. 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

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

  27. Caffeine

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

  29. 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!

  30. Caffeine Pennington and Church, 1989

  31. 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 O2 uptake (reduced HR, lactate), and enhance fat oxidation

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

  33. Ginseng (Ciwujianosides)

  34. 1.1 1.0 .9 .8 .7 RER 25 65 %VO2max Ginseng (Ciwujianosides) .5 .4 .3 .2 .1 Glycerol (mmol/L) PLA END 25 65 %VO2max Cheuvront et al., 1999

  35. Ginseng (all varieties) Effects on Human Exercise Metabolism * 2 studies used pre-post design; no placebo

  36. 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)

  37. 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

  38. 6 5 4 3 2 200 150 100 50 0 * * * CHO Plasma Glucose (mmol) Muscle Glycogen (mmol/kg) PLA CHO PLA 0 1 2 3 4 0 1 2 3 4 Cycling Time (hrs) Cycling Time (hrs) Prolonged Exercise and Fatigue Coyle et al., 1986

  39. BRAIN fTRP 5-HT 5-HT 5-HT 5-HT fTRP 5-HT fTRP BBB fTRP fTRP fTRP:BCAA --TRP A fTRP fTRP -- FFA BCAA A FFA FFA FFA FFA CAPILLARY 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

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

  41. Review of Literature

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

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

  44. 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

  45. 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.

  46. Bicarbonate: The Evidence

  47. 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 400-800m, swimming 100-200m, 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.

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