Nutritional Ergogenic Aids for Endurance Sport

Overview

• Definitions• Energy systems and endurance

exercise• Nutritional ergogenic aids for

endurance: Do they work?• Summary• Ergogenic Aid Research: Improving

the Status Quo

Definitions

Ergogenic = work (performance) enhancing

Endurance Exercise = continuous work sustained for 90 – 240 minutes

• 10 km swim• 42 km run• 100 km cycle

Classification of Ergogenic Aids

• PharmacologicalExamples: anabolic steroids, growth

hormone, erythropoietin, diuretics, etc.• Mechanical

Examples: aerodynamic clothing / helmets, oxygen supplementation, nasal dilators, etc.

• NutritionalExamples: sports drinks, creatine,

chromium, protein powders, etc.

Energy Systems

0

10

20

30

40

50

60

Rest 20% 40% 60% 80% 100%

AEROBIC POWER

FA

T (

%)

40

50

60

70

80

90

100C

HO

(%)

Brooks and Mercier, 1994

Energy Systems:Crossover Concept

0

50

100

150

200

25% 65% 85%

% VO2max

En

erg

y E

xp

en

de

d (

kc

al/k

g/m

in)

Muscle Glycogen

Plasma FFA

Plasma Glucose

Muscle TG

Contribution of Substrates to Energy Expenditure

Romijn et al., 1993

Glycogen Depletion and Fatigue

0

0.5

1

1.5

0 15 30 45 60Work Time (min)

Mu

scle

G ly

cog

en(g

/100

g w

et m

usc

le)

Bergstrom and Hultman, 1967

0

20

40

60

80

100

G VL PD

% In

itial

Mus

cle

Gly

coge

n

Hermansen, 1967; Sherman et al., 1983;Costill et al., 1988

42 kmrunning 80 min

cycling

6 x 457 mswimming

FAT

8.5 kg76,500

kcal

CHO

0.5 kg2,000 kcal

Milton, FL

Miami, FL

Nutritional Ergogenic Aids for Endurance Sport

•Carbohydrate Loading•Carnitine•Caffeine•Ginseng•Branched-Chain Amino Acids

Carbohydrate Loading

• Description:One of six classes of nutrients

• Theory:Primary energy source for exercise

above 70% VO2maxThe more glycogen that is stored,

the longer fatigue can be delayed in endurance sports

Carbohydrate Loading

Costill et al., 1985

0

20

40

60

80

100

120

140

0 2 12 24 26 36 48 50 60 72

Time (hrs)

Mu

sc

le G

lyc

og

en

(mm

ol/k

g w

et

wt.

)

High CHO Diet(8g/kg/d)

Low CHO Diet(3.5g/kg/d)

Training Bouts (2 hrs)

Carbohydrate Loading

82

9186

70

40

50

60

70

80

90

100

Day 1 Day 2

Ru

n T

ime

(m

in)

at

70

% V

O2m

ax

High CHO (9g/kg) Moderate CHO (6g/kg)

Fallowfield et al., 1993

*

PRE POST

A AB B

Bergstrom et al., 1967

0

1

2

3

4

5

0 50 100 150 200 250 300

Time to Exhaustion (m in) at 75% VO2max

In it

ial M

us

cle

Gly

co

ge

n(g

/10

0g

m u

sc

le)

r = 0.92

Low CHO Diet Normal Diet High CHO Diet

Carbohydrate Loading

Carbohydrate Loading

0

50

100

150

200

250

1 2 3 4 5 6

Days

Mu

scle

Gly

co

gen

(m

mo

l/kg

)

Costill, 1988

Classic, 1967

Modified, 1981

Mod CHOHi CHOLow CHOHi CHO

Modified Carbohydrate Loading

Day 1 Day 2 Day 3 Day 6 Day 7Day 4 Day 5

MOD CHO DIET HIGH CHO DIET

5g/kg/d 8g/kg/d

90

min

ru

n a

t 7

5%

VO

2

En

du

ran

ce E

ven

t

40

m

inru

n

40

min

run

20 m

inru

n

20

min

run

Rest

Sherman et al., 1981

-20

0

20

40

60

80

100

2 4 6 8 10

Carbohydrate Intake (g/kg/d)

Ch

an

ge

in

Mu

sc

le G

lyc

og

en

/ 2

4 h

r (m

mo

l/k

g)

2.5

5.0

7.09.0

Sherman, 1988

Carbohydrate Loading

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 Marathon2:05:42 - WR

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

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

4

3

2

1

Carnitine

YES NO

Muscle Tissue Concentration 3 1

(1987 – 1991)

Lipid Oxidation 2 6

(1985 – 1994)

Effects of Supplementation

CarnitineSTUDY POPULATION DOSE/DURATION MEASUREMENTS EFFECT

Trappe 1994

20 male athletes

4g/d – 7d Swimming performance

None

Brass1994

14 “healthy” males

93 mol/kg (IV) at start of exercise

RER, VO2, La, muscle glycogen

None

Vukovich

1994

8 “healthy” males

6g/d – 7-14d RER, FFA, glucose, VO2,

muscle glycogen

None

Barnett1994

8 “healthy” males

4g/d – 14d La, muscle carnitine

None

Colom-bani1996

7 male athletes

4g given before exercise

Marathon race performance

None

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

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

Lipolysis

HSL (inactive)

HSL (active)

AdenylylCyclase

Phospho-diesterase

cAMPkinase

TGFFAFFA

FFA

FFA

Epinephrine

+

++

_

Caffeine

+

_

Caffeine

Reference Dose Effect

Costill et al., 1978 330 mg 21 min endurance

Ivy et al., 1979 250 mg 31% FFA oxid.

Essig et al., 1980 ~350 mg 42% less glycogen

Butts et al., 1985 300 mg No improvement

Sasaki et al., 1987 300 mg 35% endurance

Erickson et al., 1987 ~350 mg 30% less glycogen

Tarnopolsky et al., 1989 ~420 mg No improvement

Graham et al., 1991 ~600 mg 55% less glycogen

Spriet et al., 1992 ~650 mg 27% endurance

Cheuvront et al., 2009

Quercetin, Caffeine Effectsin the heat (40°C)

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!

Caffeine

Food / Beverage Caffeine (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

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

Ginseng

Ginsenosides“Chinese Ginseng”

30

Ciwujianosides“Endurox”

13

Eleutherosides“Russian Ginseng”

8

Ginseng(Ciwujianosides)

Ginseng

PLA

END

Cheuvront et al., 1999

.5

.4

.3

.2

.1

25 65%VO2max

Glycerol (mmol/L) 1.1

1.0

.9

.8

.7

25 65%VO2max

RER

(Ciwujianosides)

Ginseng

YES NO

Ginsenosides (1981 – 2000) 4* 5

Eleutherosides (1986 – 1996)

2 1

Ciwujianosides (1999) 0 2

* 2 studies used pre-post design; no placebo

Effects on Human Exercise Metabolism

(all varieties)

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)

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

0 1 2 3 4

Cycling Time (hrs)

6

5

4

3

2

Pla

sma

Glu

cose

(m

mol

)

200

150

100

50

0

Mu

scle

Gly

cog

en

(mm

ol/ k

g)

***

CHO

PLA CHO

PLA

0 1 2 3 4Cycling Time (hrs)

Coyle et al., 1986

Prolonged Exercise and Fatigue

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

fTRP 5-HT 5-HT5-HT

5-HT5-HT

fTRPfTRP

A

A

BRAIN

CAPILLARY

--TRP

-- FFAFFA

FFAFFA

fTRP:BCAA

FFA

BCAA

fTRP

fTRP

fTRPBBB

fTRP

Inhibitory action on cerebral cortex, striatum, and hippocampus

Tryptophan

Hydroxytryptophan(5-HTP)

Serotonin(5-HT)

E

E

CC

S

H

Review of Literature

Performance

Reference Physical Mental

Blomstrand et al., 1991 No Difference Improvement

Blomstrand et al., 1991 Improvement

Varnier et al., 1994 No Difference

Hassmen, 1994 Improvement

Van Hall et al., 1995 No Difference

Blomstrand et al., 1995 Improvement

Madsen et al., 1996 No Difference

Blomstrand et al., 1997 No Difference Improvement

Struder et al., 1998 No Difference Improvement

Mittleman et al., 1998 Improvement No Difference

0.004

0.01

0.016

0.022

0.028

0.034

0 60 120 180 240 300

Time (min)

Pla

sma

fTR

P:B

CA

A

120

130

140

150

160

BCAA PLACTime t

o Exh

austi

on (m

in)

*

Mittleman et al., 1998

**

**

BCAA Effects in the Heat (35ºC)

Exercise

Cheuvront et al., 2004

BCAA effects in the heat when hypohydrated

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

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.

Bicarbonate: The EvidenceTime in 800 meter race under three conditions

Time (min:s)

SUBJECT CONTROL PLACEBO BICARBONATE

1 2:09.8 2:07.0 2:02.9

2 2:05.8 2:04.5 2:05.9

3 2:03.8 2:03.3 2:01.6

4 2:00.5 2:00.4 1:58.7

5 2:00.9 2:01.6 1:58.7

6 2:14.0 2:13.7 2:10.3

Mean 2:05.8 2:05.1 2:02.9*

SEM(s) 2.2 2.0 1.9

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.

Nutritional Ergogenic Aids: Evidence for Effect on

Endurance Performance

• Carbohydrate Loading

• Caffeine

• Bicarbonate

• Branched-Chain Amino Acids

• Ginseng

• Carnitine None