Athletes and bodybuilders frequently use creatine, a natural chemical compound found mostly in the muscles, to increase muscle strength and size. This sports supplement is mainly recognized for its efficacy in high-intensity training, such as sprinting and weightlifting. Evidence supporting Its usefulness for endurance training, however, is not quite so clear.
Experts Say No
Athletes looking for ways to increase their speed, strength and endurance often turn to creatine. However, while many mainstream sources, including MedlinePlus, a website of the National Institutes of Health, and the University of Maryland Medical Center agree that creatine may have a positive effect on high-intensity exercise, they do not vouch for creatine's role in promoting endurance. In fact, both MedlinePlus and the UMMC website note that creatine does not appear to improve performance in aerobic or endurance exercises.
A study published in the July 1998 issue of the "Medicine and Science in Sports and Exercise" journal attempted to determine whether creatine could have a positive effect on endurance athletes. The results were not cut and dry. Although the study found creatine to have no positive effect on cardiovascular endurance, it significantly increased interval power performance by 18 percent. This study concluded that, while creatine does not have a direct effect on cardiovascular endurance, doses of 6 grams daily does have a positive effect on short-term exercise, such as finishing spurts included in aerobic endurance exercise.
Based on a meta-analysis of five studies, Examine.com rates creatine a "C" for aerobic exercise, stating that creatine does not appear to benefit prolonged cardiovascular exercise. Endurance exercise, however, can involve more than just cardiovascular exercise. Depending on the endurance activity you're performing, creatine may be beneficial. In sports where you incorporate a burst of speed or power, creatine can prove useful under certain conditions; creatine also appears to modestly increase anaerobic cardiovascular capacity, according to Examine.com.
Safety and Side Effects
While creatine is generally considered safe, it is essential to consult a doctor before using creatine if you have any medical conditions or are taking medications. High doses of creatine have the potential to cause kidney damage, so be sure to stick with the manufacturer's recommended doses and drink 64 ounces of water per day while taking creatine, as recommended by Medline Plus. Side effects of creatine can include weight gain, muscle cramps, muscle strains and pulls, stomach upset, diarrhea, dizziness, high blood pressure and liver dysfunction.