Coffee is one of the most regularly consumed beverages in the world. In fact, I’m consuming my morning coffee whilst writing this post (yes, I acknowledge I am writing this with the bias of being a coffee drinker). The active drug in coffee is caffeine, which is found naturally in coffee beans, tea leaves, cocoa beans, and more (1). The use of caffeine in sporting settings is common, and well researched. A report has found up to 74% of athletes had detectable levels of caffeine (when undertaking drug testing in competition settings) (2). Have a think about yourself and your athletic performance. Have you ever had coffee, a caffeinated beverage, or caffeine supplements before training or competition? I suspect for the majority, the answer would be yes.
So why caffeine?
Caffeine has been shown to increase alertness, vigilance, focus, motivation, cognition, and memory, along with reducing tiredness and fatigue (3, 4). These responses are most prevalent when an individual is in a fatigued, low arousal or reduced alertness state, however the responses are still found in individuals that are unimpaired (3).
How about caffeine for athletic performance?
In general, caffeine, including coffee, improves endurance performance and reduces perceived exertion during exercise (5, 6). These performance benefits have been studied and demonstrated in sports such as cycling, running and rowing (6). In regards to running, caffeine has been show to improve the performance during time trial running (6, 7, 8) and running repeat sprinting ability (9, 10). It has also been demonstrated to Improves cycling sprint and endurance performance (6, 11, 12). Caffeine supplementation has also been shown to improve maximal strength (1RM), muscle activation and rate of activation (11, 13).
What about the mental aspect of performance? The negative impacts of mental fatigue on performance (athletic and non-athletic) are well known (14). As mentioned earlier, caffeine improves alertness, focus, motivation, cognition, and reduces tiredness and fatigue (3, 4).
It is important to note that some studies have demonstrated no benefit of caffeine supplementation (5, 15). It is thought that sports with shorter length (e.g. <3mins) may not have as significant benefit as longer endurance based sports. Some studies have also shown that believing you are ingesting caffeine can have similar effects on running as actually ingesting, highlighting the power of placebo (16).
Finally, caffeine supplementation has been shown to have equally beneficial effects for males and females (17).
Note: a large number a studies using blinding, and controls, including supplementation with caffeinated coffee and decaf coffee (often as placebo control), along with some studies also using caffeine anhydrous.
Dosage, Timing & Type:
Studies show a wide range of caffeine supplementation (1). However, typically, studies with performance benefits recommend and stick between a range of 3-6mg.kg (1, 6, 9, 10, 15, 16). There has been little evidence to suggest greater benefits with more than 6-9mg.kg (1, 5).
An example of dosing:
Athlete Weight (kg): 75kg
Dose: 225-450mg if using 3-6mg.kg
Note: this is an example only. Consider total dosing. Consider caffeine tolerance. Read disclaimer below. It is not wise to consider the same dose for all users. Variances should include men, women, caffeine users, and non-users (1).
The timing of caffeine supplementation has been recommended as 1 hour before performance/exercise (1). This is due to the peak plasma level occurring around 30-75minutes after ingestion (1).
The type of caffeine ingested can vary, including caffeine supplements, coffee, tea, sports drinks and more (1). Studies have found that coffee and caffeine anhydrous supplementation have similar results on strength and endurance performance (11, 12).
See below for visual examples of the amount of caffeine in differing beverages, including standard coffee, tea, and decaf varieties. The figure below is an example only and amounts would very depending on products and sizes.
How does it work?
It is thought that the beneficial effects of caffeine are multifactorial (1, 6, 13). The primary hypothesis is that it has a beneficial effect through central nervous system modulation (1, 5, 6, 9, 13). This is thought to be mediated by antagonism of the adenosine receptors, causing increased neurotransmitter release, dopaminergic transmission, and motor unit firing rates (1, 9, 12). Caffeine is also thought to affect the nociceptive system in the body (13). It is also thought that caffeine assists with performance through reductions in perceived exertion, and increased reaction time, cognition, and mood also having an influence on performance (1, 12).
The following figures explain the mechanistic effects in more detail.
Side Effects:
As with any drug, there are dose dependant effects. Excessive doses can have side effects, and tolerance can occur. Caffeine is shown to have withdrawal effects (1, 3). High doses have been shown to cause dizziness, headaches, jitteriness, nervousness, insomnia, gastrointestinal distress and decrease performance. It is recommended to avoid doses >9mg.kg (1). Individuals who are sensitive to caffeine have been found to have their mood and sometimes motor performance impacted (3). Due to withdrawal effects present, it is recommended to reduce caffeine consumption gradually over 3-4 days (1). The caffeine half life is 4-5 hours, and in 6-7 hours, 75% of caffeine is cleared from the body (1). This is relevant in regards to timing, and individuals should consider avoiding caffeine later in the day as it may impair sleep.
Other Health Benefits?
Finally, though not the topic of this post, coffee has been shown to be a rich source of antioxidants, with a number of potential health benefits (1). Furthermore, there is a correlation (note: doesn’t equal causation) with coffee consumption and living longer (18).
Summary:
I’d like to use a figure from Yann Le Meur to summarise caffeine, coffee and its impacts. The figure is sources from: https://ylmsportscience.com/category/caffeine/.
Disclaimer: please note, this is not medical advice. This is only general advice and should not be taken as medical advice. Individuals should consult an appropriately qualified doctor, health professional or dietician prior to undertaking a new supplement routine. It is also important for any individuals with health problems, especially heart conditions, to determine the safety and suitability for them to utilize caffeine through their doctor. Remember: caffeine is a drug, and excessive dosage can have significant negative effects.
Resources:
Sökmen, B., Armstrong, L. E., Kraemer, W. J., Casa, D. J., Dias, J. C., Judelson, D. A., & Maresh, C. M. (2008). Caffeine use in sports: considerations for the athlete. The Journal of Strength & Conditioning Research, 22(3), 978-986.
Higgins, S., Straight, C. R., & Lewis, R. D. (2016). The effects of preexercise caffeinated coffee ingestion on endurance performance: an evidence-based review. International journal of sport nutrition and exercise metabolism, 26(3), 221-239.
Yann Le Meur: https://ylmsportscience.com/category/caffeine/.
References:
1. Sökmen, B., Armstrong, L. E., Kraemer, W. J., Casa, D. J., Dias, J. C., Judelson, D. A., & Maresh, C. M. (2008). Caffeine use in sports: considerations for the athlete. The Journal of Strength & Conditioning Research, 22(3), 978-986.
2. Del Coso, J., Muñoz, G., & Muñoz-Guerra, J. (2011). Prevalence of caffeine use in elite athletes following its removal from the World Anti-Doping Agency list of banned substances. Applied physiology, nutrition, and metabolism, 36(4), 555-561.
3. Smith, A. (2002). Effects of caffeine on human behavior. Food and chemical toxicology, 40(9), 1243-1255.
4. Shields et al., (2014). The effects of a multi-ingredient cognitive formula on alertness, focus, motivation, calmness and psychomotor performance in comparison to caffeine and placebo. Journal of the International Society of Sports Nutrition, 11(1), P45.
5. Higgins, S., Straight, C. R., & Lewis, R. D. (2016). The effects of preexercise caffeinated coffee ingestion on endurance performance: an evidence-based review. International journal of sport nutrition and exercise metabolism, 26(3), 221-239.
6. Glaister, M., & Moir, G. L. (2018). Effects of caffeine on time-trial performance and associated physiological responses: a meta-analysis. Journal of Caffeine and Adenosine Research.
7. Wiles, J. D., Bird, S. R., Hopkins, J., & Riley, M. (1992). Effect of caffeinated coffee on running speed, respiratory factors, blood lactate and perceived exertion during 1500-m treadmill running. British journal of sports medicine, 26(2), 116-120.
8. Clarke, N. D., Richardson, D. L., Thie, J., & Taylor, R. (2018). Coffee ingestion enhances 1-mile running race performance. International Journal of Sports Physiology and Performance, 13(6), 789-794.
9. Glaister, M., Howatson, G., Abraham, C. S., Lockey, R. A., Goodwin, J. E., Foley, P., & McInnes, G. (2008). Caffeine supplementation and multiple sprint running performance. Medicine & Science in Sports & Exercise, 40(10), 1835-1840.
10. Carr, A., Dawson, B., Schneiker, K., Goodman, C., & Lay, B. (2008). Effect of caffeine supplementation on repeated sprint running performance. Journal of sports medicine and physical fitness, 48(4), 472.
11. Trexler, E. T., Smith-Ryan, A. E., Roelofs, E. J., Hirsch, K. R., & Mock, M. G. (2016). Effects of coffee and caffeine anhydrous on strength and sprint performance. European journal of sport science, 16(6), 702-710.
12. Hodgson, A. B., Randell, R. K., & Jeukendrup, A. E. (2013). The metabolic and performance effects of caffeine compared to coffee during endurance exercise. PloS one, 8(4), e59561.
13. Behrens, M., Mau-Moeller, A., Weippert, M., Fuhrmann, J., Wegner, K., Skripitz, R., ... & Bruhn, S. (2015). Caffeine-induced increase in voluntary activation and strength of the quadriceps muscle during isometric, concentric and eccentric contractions. Scientific reports, 5, 10209.
14. Van Cutsem et al., (2017). The effects of mental fatigue on physical performance: a systematic review. Sports Medicine, 47(8), 1569-1588.
15. Marques, A. C., Jesus, A. A., Giglio, B. M., Marini, A. C., Lobo, P. C., Mota, J. F., & Pimentel, G. D. (2018). Acute caffeinated coffee consumption does not improve time trial performance in an 800-m run: A randomized, double-blind, crossover, placebo-controlled study. Nutrients, 10(6), 657.
16. Hurst, P., Schipof-Godart, L., Hettinga, F., Roelands, B., & Beedie, C. (2019). Improved 1000-m running performance and pacing strategy with caffeine and placebo: a balanced placebo design study. International Journal of Sports Physiology and Performance, 1(aop), 1-6.
17. Clarke, N. D., Kirwan, N. A., & Richardson, D. L. (2019). Coffee Ingestion Improves 5 km Cycling Performance in Men and Women by a Similar Magnitude. Nutrients, 11(11), 2575.
18. http://theconversation.com/research-check-does-drinking-coffee-help-you-live-longer-99287.