Creatine and Exercise

Introduction  

There are many benefits associated with the use of creatine such as increased strength, increased lean body mass, and enhanced fatigue resistance which is crucial to the elderly population.  Creatine supplementation plus resistance training translates into a larger increase in bone mineral density, muscle strength, and lean tissue mass than just resistance training alone. <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="Rawson" />  It has been shown that with higher brain creatine, there comes an improved neuropsychological performance. <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="Rawson" />  Many athletes utilize creatine for body building and for the use of working out as well. It has become a more frequently used supplement by many people around the world. For older adults, the use of creatine can improve their quality of life and may reduce the disease burden on their cognitive dysfunction. Creatine is a safe and cheap supplement that has both central and peripheral effects for adults.  <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="Rawson" />

Exercise Effects

Creatine supplements can be taken to function as an ergogenice aid during exercise. Creatine supplementation increases the levels of phosphocreatine (PCr) in muslces, which is used by creatine kinase to regenerate Adenosine triphosphate (ATP) in skeletal muscle. Increased levels of PCr improves exercise performance during high intensity exercise and muscular strength and endurance. Research has evaluated the effects of polyethylene glycol (PEG) creatine supplementation taken for a 28 day period to assess its effects on anaerobic capacity. Creatine binds to PEG, which functions as a delivery system and increases the reuptake effeciency and ergogonic effects during exercise. Supplementation with PEG-creatine resulted in improved performance in vertical power, agilityt, and upper-body endurance. Some of these improvements could be due to the shortened muscle relaxation time acquired from the creatine supplementation, which would assist quickly repeated muscle movements.<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="Camic et al" /> The supplementation also caused an increase in body mass. The improvements generated by PEG-creatine supplementation would be most benefiical for untrained individuals.

Creatine loading has been evaluated for its effects on anaerobic running capacity (ARC) and body weight changes for males and females. ARC represents the theoretical distance and individual could run using only stored anaerobic energy of ATP and PCr. Creatine loading increases available ATP and PCr for creatine kinase reactions. After creatine loading, males experienced a 23% increase in ARC, but females had no significant changes. This could be due to the higher resting levels of intramuscular creatine in females, which would make them less sensitive to creatine loading. Body weight changes were small in both males and females and were mostly from increased intramuscular water volume.<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="Fukuda et al" /> Therefore, for sports involving running, creatine supplementation can be used to increase anaerobic running capacity in males without the potential to decrease performance from weight gain.

Creatine Utilization in Rehabilitation

Creatine can be very effective in the rehabilitative setting. Researchers have discovered ways to utilize creatine to aide in their interventions performed in rehabilitative settings. For instance, a study by Eijnde, Urso, Rchter, Greenhaff, & Hespel (2001) conducted a randomized control trial with twenty four subjects. All of the subjects were put into an immobilization cast for two weeks and then underwent ten weeks of rehabilitation. Half of the subjects were given creatine supplements and half were given a placebo through out the study. The researchers tested each of the subject's muscle GLUT4 content, muscle glycogen content, and muscle creatine content during immobilization and during rehabilitation. At the end of the study, the researchers concluded that creatine supplementation prevented the downregulation of GLUT4 transporters, maintained muscle glycogen content, and maintained muscle creatine content during immobilization. Creatine supplementation also helped increase muscle GLUT4, muscle glycogen, and muscle creatine levels above baseline after three weeks of rehabilitation.  This study is important in the field of rehabilitation because it may mean that athletes or individuals who become injured during exercise could have a faster recovery after their injury.

Another study related to creatine use during rehabilitation is a randomized control trial conducted by Fuld, Kilduff, Neder, Pitsiladis, Lean, Ward, & Cotton (2005). In this study, forty one patients with chronic obstructive pulmonary disease were divided into two groups. One group was given a creatine supplement, and one was not. Both of the groups completed several different tests, and they went through a pulmonary rehabilitation plan. Throughout the intervention, pulmonary function, body composition, muscle strength, exercise capacity, and quality of life were evaluated. At the end of the experiment, the patients who were taking the creatine supplement saw improvements in body composition (increase in fat free mass), muscle strength, and quality of life. These results are very significant because they suggest that patients struggling with chronic obstructive pulmonary disease may be able to improve their peripheral strength in an effort to improve their symptoms.

Creatine Utilization in the Elderly Population

The effective use of creatine as an ergogenic aid is well documented in research literature. However, there is less research available on it's use in the elderly population. The research shows that an exercise program coupled with creatine supplementation resulted in increased strength and fat-free mass in both men and women aged over 65 years when compared with exercise alone.  Interestingly enough, there is also sufficient evidence to suggest that supplementing with both creatine and protein in conjunction with exercise provides greater increases in strength and fat-free mass vs. creatine supplementation alone.  Furthermore, creatine appears to be a safe method of increasing strength and fat-free mass in elderly populations. One study argued that the time frame creatine supplements are administered could impact the muscle mass, strength, and performance of older patients . The formation of formaldehyde is commonly cited as a safety hazard associated with creatine. However, studies show that creatine supplementation does not significantly increase formaldehyde production before to after supplementation. 

Side Effects 

Oral creatine supplementation shown evidence of increased efficacy with many different athletic activities. Recently more studies are being done to research the side effects of creatine supplementation with long term use. A critical review of the current data concerning the safetly of oral creatine supplementation sheads light on many of the issues of long term use. "In healthy subjects, studies adverse effects have focused on muscle cramping, gastrointestinal symptoms, and renal/hypatic laboratory reults".  Some other less researched effects that have been found were water retention and increased work load on the kidneys. <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="Juhn" />