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Performance Enhancing Substances in Endurance Events. Kevin deWeber, MD, FAAFP Director, Primary Care Sports Medicine Fellowship USUHS. Objectives. Discuss substances used to enhance performance in endurance events Discuss any medical evidence of their safety and effectiveness.

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performance enhancing substances in endurance events

Performance EnhancingSubstancesin Endurance Events

Kevin deWeber, MD, FAAFP

Director, Primary Care Sports Medicine Fellowship

USUHS

objectives
Objectives
  • Discuss substances used to enhance performance in endurance events
  • Discuss any medical evidence of their safety and effectiveness
performance enhancing modalities
Performance Enhancing Modalities
  • Mechanical
  • Psychological
  • Physiologic
  • Nutritional
  • Pharmacologic
stimulants
Stimulants
  • Caffeine
  • Amphetamines
  • Cocaine
  • Sympathomimetics
    • Ephedrine
    • Pseudoephedrine
    • Phenylephrine
    • Phenylpropanolamine (PPA)
  • Modafinil
stimulants proven effects
Stimulants – proven effects
  • Increases Endurance
    • Increases use of free fatty acids and triglycerides
    • Spares muscle glycogen early in exercise
    • Decreased perceived exhaustion
  • Enhances Anaerobic Exercise
    • Decreases time to exhaustion
    • Decreases perception of exertion
    • Hypoanalgesic effect
  • Small amount of weight loss
stimulant use prevalence
Stimulant Use Prevalence
  • Ephedrine:
    • 3.5% in NCAA athletes
      • Clin J Sports Med 2001
    • 12% of HS boys/26% of girls have tried
      • Med Sci Sports Exer 2002
  • Caffeine
    • 33% of British club track/field athletes
    • 60% of British club cyclists
      • Chester N, Int J Sports Med 2008
caffeine s proven effects
Caffeine’s Proven Effects
  • Increased time to fatigue in prolonged, moderate intensity exercise
  • No effect on repeated sprints/heavy exercise
caffeine in endurance running
Caffeine in Endurance Running
  • 4.2-sec faster 1.5-km
  • 1-3% faster 5-km
  • 24-sec faster 8-km
  • 50-sec faster 10-km military pack march
  • No change in 21-km race
  • Improved treadmill time-to-exhaustion in marathoners
caffeine in other sports
Caffeine in Other Sports
  • Rowing: 1-3% faster 2000m race
  • Swimming: 24-sec faster 1500m race
    • About 21 min
  • Cycling: 3.5% higher mean power in 40km race
caffeine dosing
Caffeine Dosing
  • Doses 2-9 mg/kg in studies
      • 2-5 mg/kg usually effective
      • 250-500 mg
    • Cola: 40 mg
    • Coffee: 100 mg
    • Tea: 20-100 mg
    • Red Bull: 115 mg
    • Vivarin: 200 mg
caffeinated sports drinks
Caffeinated Sports Drinks
  • No proven performance benefit
    • 18-km run times
    • Pl vs carb drink vs carb+150mg caffeine
    • consumed 4x in race
    • Int J Sports Med 2005
ephedrine
Ephedrine
  • 78-sec faster 10-km run (with backpack & helmet) vs placebo
    • 30-sec faster than caffeine
      • -0.8 mg/kg
    • No benefit when added to caffeine
modafinil
Modafinil
  • Cycling at 85% VO2max
    • 22% longer time to exhaustion vs Placebo
      • 18.3 min vs 15.6
    • Central mechanism: decreased RPE
    • Dose 4 mg/kg
    • No side-efx seen
stimulants side effects
Stimulants - Side Effects
  • Anxiety*
  • Dysrhythmias*
  • Hypertension*
  • Hallucinations
  • Addiction
  • Death
stimulant regulation
Stimulant regulation
  • Most banned by USADA & NCAA
    • Ephedrine
    • PPA
    • Most ADHD meds
  • Some still allowed (cold meds)
    • Pseudephedrine
    • Phenylephrine
  • Caffeine
    • USADA: no longer monitored
    • NCAA < 15 mcg/ml
    • 1 cup coffee = 100mg = 1.5 mcg/ml in urine
blood doping
Blood Doping
  • Increasing the number of red blood cells in the body to increase the oxygen carried to muscle
    • Administration of blood, red blood cells, or related blood products
    • Erythropoietin
      • Stimulates bone marrow to produce red blood cells
blood doping proven effects
Blood Doping – proven effects
  • 7% increase in Hgb
  • 5% increase in VO2 max
  • 34% increase in time to exhaustion at 95% VO2 max
  • 44 second improvement in 5 mile treadmill run time

(Williams and Branch summarized study findings)

blood doping side effects
Blood Doping - Side Effects
  • Transfusion reactions
  • Infections
  • Increased viscosity of blood
    • Stroke, MI, PE
blood doping regulation
Blood Doping - regulation
  • Erythropoietin only by prescription
  • Doping banned by USADA, NCAA
  • Blood tested for antigens
  • Ceiling on allowable Hct level at 50
beta 2 agonists
Beta-2-Agonists
  • Physiology
    • Bronchodilation, increased ventilation
    • Examples: albuterol, terbutaline, salmeterol
beta 2 agonists proven effects
Beta-2-Agonists – proven effects
  • Clear benefit in asthma and EIB
    • Increased ventilation
  • No increase in performance in NON-asthmatic athletes
  • Side effects: tremor, tachycardia
  • Regulation
    • USADA: prohibited
    • NCAA: inhalation permitted
creatine
Creatine
  • Replenishes ATP in anaerobic exercise
  • No federal assessment of quality, performance, or safety
  • Proven to increase lean body mass, strength
creatine disproven effects
Creatine – disproven effects
  • Meta-analysis 2003:
    • No significant difference in field-based athletic performance (e.g. running, swimming)

X

X

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Branch JD. Int J Sports Nutr Exerc Metab June 2003

creatine side effects
Creatine - Side Effects
  • Studies of 2-10 weeks: no side efx
  • Long term:
  • 40% non-responders
anabolic steroids
Anabolic Steroids
  • Analogs of testosterone
  • More than 100 types
  • Forms:
    • Oral
    • Injection
    • Topical (gels, creams)
  • Prevalence of use
    • 2001: 1% in US college athletes
    • 2006: 13% of German fitness center attendees had used in past
anabolic steroids proven effects
Anabolic Steroids – Proven Effects
  • Increase in fat-free mass
  • Increase in body weight
  • Increase in arm girth
  • Increase in leg girth
  • Increase in bench press and squat scores
anabolic steroids disproven effects
Anabolic Steroids—Disproven Effects
  • No effect on endurance exercise
    • Males on treadmill
      • Eur J Appl Physiol 2006
    • VO2max in rats
      • Med Sci Sports Exer 2004
anabolic steroids side effects
Anabolic Steroids - Side Effects
  • Hepatocellular damage
  • Cardiovascular disease
  • Psychological disturbance

Effects can sometimes be permanent!

more side effects
More side effects…
  • Men
    • Acne
    • Premature baldness
    • Prostatic hypertrophy
    • Female masculinization
    • Injection complications*
    • Testicular atrophy
    • Impotence*
    • Gynecomastia*

(some may be permanent)

nitric oxide releasing agents
Nitric Oxide-releasing agents
  • Physiology
    • Arginine is a precursor of NO
    • NO regulates BP and blood flow to organs
    • Most supplements: Arginine α-ketoglutarate
  • Claims
    • Improves “pump” and blood flow to muscles
    • Increases strength and size
    • Speeds recovery
nitric oxide releasing agents1
Nitric Oxide-releasing agents
  • Endurance exercise studies
      • No benefit in endurance athletes
      • Limited evidence of benefit in debilitated pts
  • Strength exercise: mixed results, no proven benefit
  • More studies needed
sodium bicarbonate
Sodium Bicarbonate
  • Mechanism: buffers metabolic acidosis after strenuous exercise
  • Proven ergogenic efx in high-intensity exercise
    • 100m & 200m swim
    • Repeated sprints
    • Repeated judo throws
bicarbonate
Bicarbonate
  • Limited & conflicting evidence of benefit in aerobic exercise
    • High-intensity running: 17% better time-to-exhaustion (30 vs 26 min)
    • 60-min max-effort cycle ergometry: 14% higher power vs Placebo
    • 60-min high-intensity cycling: no difference vs Placebo
bicarbonate1
Bicarbonate
  • Dose: 0.2 - 0.3 mg/kg
  • GI side effects common
carbs
Carbs
  • Sports drink consumption
  • Carbohydrate loading
sports drink consumption
Sports Drink Consumption
  • Evidence supports enhanced endurance performance vs water in events >60 min
  • No benefit from added protein
carbohydrate loading
Carbohydrate Loading
  • Known to increase muscle glycogen levels 13% - 100%
  • Prolongs time to exhaustion 2-3% in endurance events >90 minutes
  • Higher effect in Untrained persons
    • 25-km treadmill
methods of carbo loading
Methods of Carbo Loading
  • Classic 6-day regimen
    • 3 days intense glycogen-depleting exercise
    • 3 days high-CH diet, no exercise
  • Modified 6-day regimen
    • 3-day exercise taper, normal diet
    • High-CH (70%) & light exercise 3d prior
  • Single-day regimen
    • 10 gm/kg/day CH 1-day prior
    • Normal exercise regimen
carbohydrate loading s
Carbohydrate Loading ‘s
  • Little standardization of methods
    • Athletes need to try methods prior to competition to see what works
  • Exact roles of glycogen-depleting exercise, type of CH, and timing are unclear
miscellaneous losers in endurance exercise performance
Miscellaneous Losersin endurance exercise performance
  • Vitamin E and other vitamins
  • Minerals: Cr, Mg, Zn, Se
  • L-Carnitine
  • Antioxidants
  • Pyruvate
  • Arginine
  • Hydroxy-methyl-butyrate (HMB)
anti doping in elite athletic competition
Anti Doping in Elite Athletic Competition
  • Permitted/Prohibited?

http://www.usantidoping.org.dro

1-800-233-0393

therapeutic use exemptions tue
Therapeutic Use Exemptions- “TUE”
  • Abbreviated TUE
    • Doc fills out; athlete faxes to USADA
    • Effective immediately, up to 1 year
    • IM/IJ/inhaled corticosteroids
    • Inhaled beta-agonists
  • Regular TUE
    • All other substances
    • Doc fills out, send to USADA, along with supporting documents
    • Process takes 1-2 months to approve
    • Variable duration
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