Caffeine’s benefits to athletic performance

Posted on May 22, 2010 by Jeffrey Newman

Caffeine, an alkaloid, primarily acts as a central nervous system stimulant and ninety percent of competitive athletes consume it. Caffeine crosses the blood brain barrier and cellular membranes of all tissues in the body. This allows it to affect many tissues, including the central nervous system. Caffeine plays a significant role in cognitive performance during sleep-deprivation activities such as those in military units. Results include improved vigilance, reaction time and alertness, all of which are important for 24-hour races.
Caffeine decreases the body’s reliance on muscle glycogen, the storage form of carbohydrate, and increases its use of fat stored within the muscle for energy production. When caffeine is consumed with carbohydrate during exercise, it increases the body’s absorption and use of consumed carbohydrates rather relying on use of glycogen. Both are important for sustaining endurance and for increased work production, as the body has finite carbohydrate stores but plenty of fat for energy utilization by contracting muscles. Caffeine greatly increases Beta-endorphin release, lasting up to two hours after exercise. Caffeine’s stimulated endorphin release correlates with athletes’ decreased pain perception and perceived exertion. This allows an athlete to continue exercising, surpassing the limit or threshold for pain and discomfort. Because of caffeine’s mechanisms, sports lasting longer than an hour with sustained effort will benefit more from players consuming caffeine than sports with short bursts and duration. Endurance sports such as running, cycling and cross country skiing, high-intensity sports such as swimming and rowing, and team sports such as soccer and field hockey all benefit from caffeine supplementation by allowing players to increase work production, speed and accuracy. Caffeine does not offer a performance-enhancing benefit for strength and power activities, such as resistance training. Caffeine supplementation of 3 to 6 mg per kilogram of body weight one hour before exercise is most effective. Consuming more caffeine does not improve performance, however, and has potential side effects such as elevated heart rate and blood pressure, tremors and restlessness. Hydration is a concern for sports performance, and when consumed during exercise, caffeine does not increase fluid loss.

References:

• “Aviation, Space and Environmental Medicine”; Caffeine Effects on Physical and Cognitive Performance During Sustained Operations; McLellan et al.; September 2007
• “Journal of Applied Physiology”; Caffeine Increases Exogenous Carbohydrate Oxidation During Exercise; Yeo et al.; September 2005
• “Journal of Clinical Endocrinology and Metabolism”; Effects of Caffeine on Muscle Glycogen Utilization and the Neuroendocrine Axis During Exercise; Laurent et al.; June 2000
• “Journal of the International Society of Sports Nutrition”; International Society of Sports Nutrition Position Stand: Caffeine and Performance; Goldstein et al.; January 2010
• “Medicine and Science in Sports and Exercise”; Enhancement of 2000-m Rowing Performance After Caffeine Ingestion; Bruce et al.; November 2008