And I quote
"As your running intensity increases, more and more lactate is produced with eventually results in your blood becoming more acidic. This is one of the primary causes of fatigue in 5K and 10K races. The Texas A&M study uses the services of 44 volunteers who performed bouts of high intensity interval training on stationary cycles. The study showed that the group that used a creatine supplement produced less post exercise lactic acid. "
"Effects of Creatine in Ammonia and Lactate Levels
In a study(1) that was looking at the effects of creatine in the muscle metabolism and endurance of people with congestive heart failure, researchers found that lactate and ammonia levels were lower on the group supplemented with 20 grams of creatine. These two metabolites increase during exercise, both aerobic and anaerobic, and high levels impair performance and recovery. Therefore, one can conclude that creatine can offer the endurance runner faster recovery from the long runs since supplementing with creatine will enhance the body's metabolism in such a way that allows for better handling of lactate and ammonia levels. "
(1)Andrews R., et al. The effect of dietary creatine supplementation on skeletal muscle metabolism on congestive heart failure. Eur Heart J 1998 Apr; 19(4): 617-22.
(2)Schedel JM, et al. Acute creatine loading enhances human growth hormone secretion. J Sports Med Phys Fitness 2000 Dec;40(4):336-42.