Key points on caffeine and athletes:
It’s no secret that the best endurance athletes in the world start their morning out with a cup of coffee or two before heading out the door for a workout or race.
Besides being the “best part of waking up,” and tasting damn fine, caffeine sparks several physiological processes in the body that can benefit both the elite endurance athlete and average joe alike.
This article will answer your most pressing questions about caffeine such as:
Caffeine (1,3,7-trimethylxanthine) is the most widely consumed drug in the world and is commonly used by athletes, both recreational and professional, for performance enhancement.
In the United States, over 70% of caffeine intake comes from coffee, followed by soft drinks and tea, although energy drinks and sports gels and chews containing caffeine are quickly gaining popularity for use before and during competition.
Caffeine is also frequently found in pre-workout supplements and weight loss products, often in multiple forms.
With caffeine use so widespread among athletic populations, one must question its effectiveness regarding improving sports performance, and also whether there are any negative side effects from acute (short-term) or chronic (long-term) consumption.
Caffeine is absorbed rapidly by the gastrointestinal tract and enters the bloodstream within 15-45 minutes of consumption, with peak blood concentrations evident about one-hour post-ingestion.
Its rapid absorption rate makes caffeine an effective endurance pre-workout supplement, since it doesn’t need to be “loaded” for days or weeks, and you can take it in a targeted manner just before a competition or training session.
Many consume caffeine for its effects as a central nervous system (CNS) stimulant in order to increase focus and alertness, but there is also evidence that the benefits of caffeine supplementation extend beyond these effects, specifically prolonged endurance, increased metabolic rate, enhanced fat metabolism, and improved neuromuscular function.
Caffeine is thought to work via three primary physiological mechanisms:
Improvements in endurance performance following caffeine intake have been observed consistently in events lasting 15-120 minutes at an intensity of 70-75% VO2max, in time trial performances (simulating competitive events such as the 10k), and in time to exhaustion tasks in cycling and running.
Pasman and colleagues examined the effect of varying quantities of caffeine on endurance performance.
Nine aerobically trained cyclists performed six rides to exhaustion at approximately 80% maximal power output.
Subjects consumed four treatments on separate occasions: placebo, 5, 9, and 13 mg/kg of caffeine in capsule form.
Results were conclusive in that all three caffeine treatments significantly increased endurance performance as compared to placebo.
Moreover, there was no statistical difference between caffeine trials.
Therefore, increases in performance were comparable for both the moderate dose of 5 mg/kg as well as the high dose of 13 mg/kg.
The average increase in performance time was 27% for all three caffeine treatments.
Results from that paper indicated no statistical advantage for consuming an absolute dose of 300 mg, as opposed to 200 mg.
However, the 200 mg dose did result in significant improvements in performance, as compared to 100 mg, and 100 mg was at no point statistically different or more advantageous for performance than placebo.
In an earlier study published by Graham and Spriet, seven elite runners performed a total of four trials, two cycling to exhaustion and two running to exhaustion at approximately 85% VO2max.
Times for running and cycling were both significantly improved, running increased from ~49 min for placebo to 71 min for 9 mg/kg of caffeine, cycling increased from ~39 min for placebo to ~59 min for 9 mg/kg of caffeine.
Results were comparable in a separate 1992 Spriet et al. publication.
In a crossover design eight subjects consumed both a placebo and caffeine treatment at 9 mg/kg and 60 minutes later cycled to exhaustion at ~80% VO2max. Once again, following caffeine supplementation times to exhaustion were significantly increased.
Results indicated subjects were able to cycle for 96 min during the caffeine trial, as compared to 75 min for placebo.
Recently McNaughton et al. reported the effects of a moderate dose of caffeine (6 mg/kg) on 1-hour time trial performance.
This investigation is unique to the research because, while continuous, the protocol also included a number of hill simulations to best represent the maximal work undertaken by a cyclist during daily training.
The caffeine condition resulted in the cyclists riding significantly further during the hour-long time trial, as compared to placebo and control. In fact, time trial performance was improved 4-5% by the caffeine treatment over the other two treatments.
The use of caffeine in anhydrous form, as compared to a cup of caffeinated coffee, seems to be of greater benefit for the purpose of enhancing endurance performance.
In addition, a low-to-moderate dose of caffeine between 3 and 6 mg/kg appears to be sufficient for enhancing performance in a maximal sustained endurance effort.
In short, YES and yes!
Despite popular belief, current research does not support the notion of caffeine-induced dehydration during exercise, or any change in fluid balance that could be detrimental to performance (Goldstein et al. 2010).
High doses of caffeine (≥ 9 mg/kg body weight) have been associated with increased anxiety, palpitations, restlessness, headache, difficulty sleeping, and gastrointestinal distress, particularly in non-habituated users.
Caffeine toxicity is extremely rare, due to the amount that would be required to reach lethal limits in the blood (5-10 grams, or roughly the equivalent of drinking 75 cups of strong brewed coffee over a short time period).
Caffeine has many potential benefits for endurance performance and appears to be ergogenic in most exercise situations.
Improved energy, increased concentration, and alertness are the primary reasons for caffeine consumption.
Athletes and trained individuals seem to benefit more than untrained individuals, at least as far as performance is concerned.
Side effects and adverse events are generally mild and occur more often in naive users, with dosages ≥ 9 mg/kg known to increase their incidence.
Be sure to read labels and know how much caffeine is in the products you are taking, particularly if you consume more than one type of caffeine-containing product daily (thermogenic, pre-workout, caffeinated beverages, etc.).
As with most interventions, individual results may vary.
Anderson, D.E. (2013). Caffeine. In A.E. Smith-Ryan & J.A. Antonio (Eds.), Sports nutrition & performance enhancing supplements (pp. 201-223). Ronkonkoma, NY: Linus Learning.
Astorino, T. A., & Roberson, D. W. (2010). Efficacy of acute caffeine ingestion for short-term high-intensity exercise performance: a systematic review. J Strength Cond Res, 24(1), 257-265. doi: 10.1519/JSC.0b013e3181c1f88a
Astrup, A., Toubro, S., Cannon, S., Hein, P., Breum, L., & Madsen, J. (1990). Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers. Am J Clin Nutr, 51(5), 759-767.
Diepvens, K., Westerterp, K. R., & Westerterp-Plantenga, M. S. (2007). Obesity and thermogenesis related to the consumption of caffeine, ephedrine, capsaicin, and green tea. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 292(1), R77-R85.
Goldstein, E. R., Ziegenfuss, T., Kalman, D., Kreider, R., Campbell, B., Wilborn, C., . . . Antonio, J. (2010). International society of sports nutrition position stand: caffeine and performance. J Int Soc Sports Nutr, 7(1), 5. doi: 10.1186/1550-2783-7-5
Graham, T. E. (2001). Caffeine and exercise: metabolism, endurance and performance. Sports Med, 31(11), 785-807.
Jeukendrup, A. E., & Randell, R. (2011). Fat burners: nutrition supplements that increase fat metabolism. Obesity reviews, 12(10), 841-851.