Studies have had mixed results since people vary dramatically in their responses to caffeine. It is difficult to know if an athlete will notice a difference in performance, since those who consume caffeine regularly will likely have a higher tolerance to caffeine's effects compared to an athlete who doesn't consume it at all.
- Reduced perception of fatigue (RPE)
- Stimulates the nervous system, which can lead to greater productivity
- It reduces the amount of glycogen (carbohydrate) used in the first 15 minutes of exercise by 50% allowing athletes to delay the onset of fatigue.
- Has been linked to stronger and more powerful muscle contractions
- Stimulates the brain and contributes to clearer thinking and increased concentration
- Ingesting caffeine can have an average of 6-9% improvement in endurance performance.
Excessive caffeine intake can cause various side effects:If you plan on introducing caffeine into your training, take a slow approach with gradual increases in intake while keeping a close eye on performance and monitor your body’s response.
- tremors, heart palpitations, jitters
- nervousness, irritability
- gastrointestinal distress
References from the SIRC Collection:
1. Ahrens J, Crixell S, Lloyd L, Walker J. THE PHYSIOLOGICAL EFFECTS OF CAFFEINE IN WOMEN DURING TREADMILL WALKING. Journal Of Strength & Conditioning Research (Allen Press Publishing Services Inc.). February 2007;21(1):164-168.
2. Goldstein E, Ziegenfuss T, Antonio J, et al. International society of sports nutrition position stand: caffeine and performance. Journal Of The International Society Of Sports Nutrition. January 2010;7:1-15.
3. Mickleborough T. Caffeine's Effect on Time-Trial Performance. Triathlete . June 2010;(314):149-151.
4. SÖKMEN B, ARMSTRONG L, MARESH C, et al. CAFFEINE USE IN SPORTS: CONSIDERATIONS FOR THE ATHLETE. Journal Of Strength & Conditioning Research (Lippincott Williams & Wilkins). May 2008;22(3):978-986.
5. Tunnicliffe J, Erdman K, Reimer R, Lun V, Shearer J. Consumption of dietary caffeine and coffee in physically active populations: physiological interactions. Applied Physiology, Nutrition & Metabolism. December 2008;33(6):1301-1310.
6. Vanata D, Mazzino N, Bergosh R, Graham P. Caffeine Improves Athletic Performance among Division II Collegiate Swimmers. Journal Of The Academy Of Nutrition & Dietetics. September 2, 2012;112:A89.