Creatine is an organic compound naturally found in muscle cells, where it plays a significant role in energy production. The body synthesizes creatine from amino acids, and it is present in foods like red meat and fish, but it is widely used as a dietary supplement. Creatine gained popularity for enhancing performance in activities requiring strength and power, such as weightlifting. For runners, who focus on endurance and speed, the utility of this supplement is often questioned. This article evaluates its specific impact on different running demands and training protocols.
The Physiological Role in Running
Creatine’s action in the muscles centers on the rapid energy system known as the phosphocreatine (PCr) system. Muscle cells store creatine primarily as phosphocreatine, which serves as a reserve to quickly regenerate adenosine triphosphate (ATP). ATP is the immediate fuel source for all muscle contractions, but its stores deplete rapidly during high-intensity exercise.
When a runner engages in a sudden burst of speed, such as a sprint or hill climb, the PCr system immediately restores ATP. This process allows for the maintenance of maximum effort for a few extra seconds. Supplementing with creatine increases intramuscular PCr stores by about 20%, enhancing the muscle’s capacity for rapid ATP recycling. This mechanism is relevant to running activities that involve repeated, short-duration maximal efforts.
Performance Impact for Different Running Distances
The performance benefits of creatine depend highly on the type of running performed. For short-distance, anaerobic efforts, the evidence strongly supports its benefits. Runners in events like the 100-meter or 400-meter dash, or those performing repeated interval training, experience improved power output and reduced fatigue. The increased PCr stores help sustain maximal effort over successive sprints, allowing for higher quality training.
For long-distance running, which relies predominantly on aerobic metabolism, the direct performance benefits diminish significantly. Aerobic running, such as a marathon, uses oxygen to break down fats and carbohydrates for fuel, a process that does not rely on the PCr system. However, creatine may offer indirect benefits for endurance athletes by supporting faster recovery between high-intensity training sessions. Creatine can also enhance muscle glycogen storage, a fuel source that delays fatigue during prolonged endurance events.
Managing Concerns: Weight Gain and Hydration
A common concern among distance runners is the potential for weight gain and its effect on running efficiency. Creatine is an osmotic compound, meaning it draws water into the muscle cells. This results in an increase in total body water, leading to a temporary weight gain of approximately 1 to 2 kilograms during the initial supplementation phase. This weight gain is due to increased intramuscular water and should not be mistaken for body fat.
For runners competing where lower body mass is advantageous, this temporary weight increase may slightly offset strength or power benefits. However, the increased water promotes a state of cellular hydration that can be protective. Early concerns that creatine causes dehydration or muscle cramping have largely been refuted by research. Scientific literature suggests creatine supplementation does not impair the body’s ability to regulate temperature or fluid balance, and may even help improve total body water, provided the runner maintains adequate fluid intake.
Practical Supplementation Guidance
The most studied and recommended form of the supplement is creatine monohydrate due to its efficacy and cost-effectiveness. Runners have two primary strategies for initiating supplementation to saturate muscle stores. The fastest method is a loading phase, which involves consuming 20 to 25 grams per day, split into several doses, for five to seven days. This initial phase is followed by a maintenance dose of 3 to 5 grams daily to keep muscle stores elevated.
Alternatively, a runner can bypass the loading phase and begin with the daily maintenance dose of 3 to 5 grams. While this minimizes the chance of initial weight gain and potential gastrointestinal discomfort, it takes longer, typically three to four weeks, to fully saturate the muscle cells. The timing of the daily dose is less important than consistency, though taking creatine with carbohydrates may enhance its absorption.