Creatine. Overview. Travis Harvey, PhD, CSCS

Transcription

1 Creatine Travis Harvey, PhD, CSCS Overview This is not exhaustive it s applicable Disclaimer BLUF Myths Legends Protective effects Move, Shoot, Communicate

2 Bottom Line Collectively, results from these studies suggest there is no reason to believe creatine enhances the risk of dehydration or muscle cramps." Watson G, Casa DJ, Fiala KA, et al. Creatine use and exercise heat tolerance in dehydrated men. J Athl Train 2006;41: Powers ME, Arnold BL, Weltman AL, et al. Creatine Supplementation Increases Total Body Water Without Altering Fluid Distribution. J Athl Train 2003;38: Kern M, Podewils LJ, Vukovich M, et al. Physiological response to exercise in the heat following creatine supplementation. In: Journal of Exercise Physiology Online 2001: Volek JS, Mazzetti SA, Farquhar WB, et al. Physiological responses to short term exercise in the heat after creatine loading. Med Sci Sports Exerc 2001;33: Weiss BA, Powers ME. Creatine supplementation does not impair the thermoregulatory response during a bout of exercise in the heat. J Sports Med Phys Fitness 2006;46: BLUF Creatine Monohydrate is: Safe Performance Enhancing Good for hot work Good for dehydration Good for disease Good for fatigue Creatine Monohydrate is not: Unsafe Damaging to the body or brain Steroids Bad for females Bad for kids Basics What Amino acid synthesized from arginine, glycine, and methionine in the kidneys, liver, and pancreas Monohydrate currently most cost effective form Benefits Increased strength, power, and lean body mass (Buford, 2007) Increased ability to perform a given sub maximal workload at a lower oxygen cost coupled with reduced work by the cardiovascular system. (Nelson et al., 2000) Possible neuroprotective effects (Klivenyi, 1999) Increased thermoregulation in heat (Dalbo, 2008)

3 Basics Brief history: 1835 beef 1927 cats 1967 humans ATP 1970s rat and chicken embryos increased growth 1981 visual impairment subjects increased strength 1992 human SKM creatine concentration increased 1992 Olympic 100m champion reportedly ingested studies on athletic performance Dalbo et al., Putting to rest the myth of creatine supplementation leading to muscle cramps and dehydration. Br J Sports Med 2008;42: Jager et al. Analysis of the efficacy, safety, and regulatory status of novel forms of creatine. Amino Acids May;40(5): Basics Absorption into target tissue is key Phosphocreatine increase more P for ATP

4 Basics When Single doses at any time More research needed to demonstrate if timing is important Serum vs. Intramuscular How much 0.3 g/kg/day divided into ~5 equal doses if loading 0.03 g/kg to 3 g per day for maintenance Notes May not be as effective when taken with caffeine (Vandenberghe et al., 1996) Myths It s only water weight gain Total Body Water and Intracellular Water may increase for a short time (Groeneveld vs. Dalbo), though not always initially (Powers et al., 2003) Causes kidney damage Urea, micro albuminuria, and creatinine production NOT increased with prolonged use (Groeneveld et al., 2005) Cramping and Dehydration Creatine likely inhibits both (Dalbo, 2008) Heat Injury Risk possibly improved with creatine (Watson et al., 2006) A steroid that should be cycled Creatine is not a steroid Long term research shows cycling is unnecessary (Poortmans et al., 1997, 1999, & 2005) Myths The Beginning 1998 case report in The Lancet (Pritchard & Kalra, 1998) 25 year old male with kidney disease Experienced renal function deterioration Physician discontinued creatine use normal kidney function restored 3 days later, L Equipe reports kidney function impairment b/c of creatine 4 studies had already demonstrated no renal stress from creatine (Almada et al., 1996; Poortmans et al. 1997; Earnest et al., 1996; Poortmans & Francaux, 1998)

5 Myths 10 years later, myths still believed by public and medical professionals Muscle Cramps Dehydration Heat tolerance Organ Damage Water Weight Based on creatine s water dragging actions into cells Initial 5 day, 20 g/d dose increases body mass ~1 3 kg (Kraemer & Volek, 1999) Theory of water being retained intracellularly (Williams & Branch, 1998) and not being released to extracellular compartment for thermoregulation (Powers et al., 2003) Mass gained not all water (Powers et al., 2003) At 5 g/day, significant body mass increase Days 1 28, but not Days 1 7. Suggests protein synthesis, not just water retention Muscle Cramps Surveys of athletes have indicated muscle cramps, dehydration, diahhrea, etc. 75% exceeded 5g/d and 35% ingested g/d as a maintenance dose (Juhn et al., 1999) These studies typically don t controlled or ask about other supplements being used. When surveys ask about other supplements: 43% yes rate (Greenwood et al., 2000) Blame creatine for medical problems anyway (Koshy et al., 1999; Thorsteindottir et al., 2006)

6 Dehydration Heat Creatine increases plasma volume during hot exercise Heat Creatine improves response to heat by ~32 F Creatine improves HR response, core temp, and sweat rate during exercise.

7 Heat Heat and Hydration Organ Damage Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN.

8 Legend Gender CrM loading at 20 g/d for 7 days Cycling 70 75% VO2max 24degC ~33% RH No differences in rectal or skin temp No differences in HR

9 Legend Legend Move

10 Shoot Communicate Summary Shoot, Move, and Communicate better with creatine monohydrate Dose it at 0.03 g/kg/d Sugar not required, but better absorption Creatine is no longer only a supplement for performance enhancement It s a part of a larger treatment and training strategy