The benefits of creatine for strength and muscle mass are well established, making it one of the most widely used supplements, alongside protein, in gyms and sports dominated by strength and explosive power. Creatine mainly improves performance by increasing energy availability for short-duration exercise. Although less popular in this population, it can also be highly relevant to endurance athletes.
Glycogen glycogen is the main energy substrate during moderate- and high-intensity exercise. Depletion of glycogen stores therefore limits performance, as illustrated by the dreaded marathon wall. During endurance exercise, creatine does not provide the same immediate energy benefits as it does during short efforts, but it may reduce glycogen use during exercise and support replenishment afterward.
One study1 of athletes running for 60 minutes at moderate intensity (60-75% VO2max) found that creatine monohydrate supplementation (12 g per day for 15 days) reduced protein breakdown and glycogen use, reflected in lower post-exercise lactate. Other authors2 found that supplementation (3 g per day for 28 days) increased resting and post-exercise glycogen and reduced oxygen consumption by 10% during a two-hour moderate-intensity cycling test, indicating greater energy efficiency.
Figure 1. Recovery of glycogen levels after an intense session. The graph shows significantly greater recovery when creatine was consumed with carbohydrates than with carbohydrates alone.
Therefore, creatine supplementation may reduce glycogen use during exercise and delay fatigue. Creatine also appears to support post-exercise glycogen replenishment, which is essential for subsequent sessions. In a recent study3, after an exercise session that reduced glycogen stores—cycling to exhaustion at 70% VO2max—creatine supplementation (20 g per day for 6 days) combined with a high-carbohydrate diet restored glycogen much faster than carbohydrates alone.
Although creatine is less widely used by endurance athletes than by people seeking hypertrophy or strength gains, growing evidence supports its benefits. It may be especially useful during high-load periods requiring optimal performance across several closely spaced sessions, such as double training days or consecutive high-intensity sessions. In these cases, 20 grams per day, divided into 4 doses of 5 grams, with a high-carbohydrate diet can increase creatine stores and support glycogen recovery.
References
1. Tang FC, Chan CC, Kuo PL. Contribution of creatine to protein homeostasis in athletes after endurance and sprint running. Eur J Nutr. 2014;53(1):61-71. doi:10.1007/s00394-013-0498-6.
2. Hickner RC, Dyck DJ, Sklar J, Hatley H, Byrd P. Effect of 28 days of creatine ingestion on muscle metabolism and performance of a simulated cycling road race. J Int Soc Sports Nutr. 2010;7:26. doi:10.1186/1550-2783-7-26.
3. Roberts PA, Fox J, Peirce N, Jones SW, Casey A, Greenhaff PL. Creatine ingestion augments dietary carbohydrate mediated muscle glycogen supercompensation during the initial 24 h of recovery following prolonged exhaustive exercise in humans. Amino Acids. 2016;48(8):1831-1842. doi:10.1007/s00726-016-2252-x.
AUTHOR
Pedro Valenzuela
Researcher in the Physiology Unit at the University of Alcalá and the Performance Monitoring Unit at the Sports Medicine Center (AEPSAD, Madrid High Performance Center).
Website: www.fissac.com
