How Athletes Use Caffeine to Boost Performance

Using caffeine to perk up your morning or get through an afternoon slump is pretty standard. So it makes sense to consider using the substance to supercharge your fitness performance. If you’re wondering whether to caffeinate pre-workout here’s what you need to know:

Caffeine works by blocking adenosine from binding to its receptors in the brain. This prevents signaling to the brain that you need rest, stimulates adrenaline and promotes the effects of dopamine. That’s the short story of how caffeine seems to offer a hit of extra energy. This is all great for giving yourself a morning boost, powering through an afternoon meeting and crushing that extra rep in the gym.

Speaking of that last one … caffeine is well-known as a performance enhancer due to blocking that feeling of fatigue. Research shows 75–90% of athletes turn to caffeine to boost their energy and get through competition without fading.

There are three types of people when it comes to caffeine: hypersensitive, hyposensitive and normal sensitivity. If you drink half a cup of coffee and feel jittery, then you’re hyper (very) sensitive and should limit, if not totally avoid, caffeine. If you can have a triple latte and go take a nap, you are likely hypo (not very) sensitive to the substance and might have to consume higher-than-average amounts to see any effects. If you fall somewhere in between these categories, then you’re like 80% of the population and have normal caffeine sensitivity. Normal consumption is considered 300–400mg of caffeine a day which is about 2–3 8-ounce cups of coffee.

Caffeine content is not as straightforward as you might think. When it comes to coffee, the type of beans and roasting method matters. A shot of espresso has less caffeine than a cup of black coffee, dark roast has less than the same amount of light roast and instant coffee contains even less than dark roast. It’s also important to remember decaf coffee is not 100% caffeine-free; each cup has roughly 4mg, which isn’t much but can add up if you’re consuming a pot a day. Energy drinks contain a huge range of caffeine from 80mg for the popular Red Bull to more than 300mg from the powerful (and potentially dangerous) Redline. Energy drinks typically pair caffeine with unregulated stimulants, so exercise caution if consuming such products. Tea, soda and chocolate also contain caffeine at amounts similar to a cup of coffee or less. Other products that contain caffeine at extremely variable amounts are products where the substance has been added for supplemental purposes including waters, sport gels, bars, gums and pills.

The high usage of caffeine by athletes is due to the substance being readily available, easy to integrate into a nutrition strategy and legal in competition where drug testing occurs. It also provides a high potential for increased performance. Like any nutrition topic, there are results pointing in both directions, but most research points to caffeine being a clear performance aid, so we are taking the stance that, yes, caffeine helps.

Specifically, caffeine seems to help with endurance events. In research these are athletic efforts lasting longer than 5 minutes with the acknowledgment that the longer the event, the more caffeine assists performance. This performance-enhancing ability is due to caffeine’s effect on the central nervous system, ability to blunt pain, increase mood, reduce fatigue and improve mental cognition.

A well-documented study on 5K runners found caffeine at a dose of 5mg/kg provided a 1% increase in race times. While 1% may not seem like much, it equates to 12 seconds shaved off a 20-minute effort — and that’s not a bad improvement for such a short race. That same increase for a marathon would be almost 2 minutes off a 3-hour race and any athlete would take a 2:58 over a 3:00, especially if all they had to do was drink coffee. In two studies, one with women cyclists competing an 8.2km time trial and another using mixed genders completing a 10km time trial, caffeinated times were roughly half a minute faster than non-caffeinated times. Again, that might not seem like much, but races have been won and lost by far less than 30 seconds.

As previously mentioned, caffeine increases the effects of dopamine, making you feel happier and potentially less phased by difficult efforts. The substance also provides a pain-reducing effect, meaning you may feel less soreness after heavy efforts. Studies testing caffeine on sleep-deprived soldiers point to clear effects on increased mental focus and athletes know mental strength goes a long way in promoting physical strength. There is thought that ingesting caffeine stimulates fat utilization, which provides performance-enhancing benefits, but studies show extremely mixed results when studied. Others believe caffeine boosts performance by enhancing the gut’s ability to absorb glucose from sources consumed during the effort.

There is a gender gap when it comes to caffeine. Studies specifically done on women and caffeine show women see performance gains, but they might come without realizing it; power and time were improved in cycling time trials with caffeine usage but no reduction in perceived effort was reported, while men reported the effort seemed easier after caffeine was consumed. Caffeine is also metabolized more slowly in females, meaning women need to ingest caffeine earlier in the workout than men and may experience a slightly higher diuretic (although still insignificant) effect.

Besides your body’s trained ability to utilize caffeine, athletes at every stage of training should pay attention to how well they can take in caffeine while performing a serious effort. Caffeine is known to stimulate the gastric system, leading to impromptu bathroom breaks. This is why we practice and train with nutrition strategy to ensure what is taken in is not going to lead to negative outcomes. Caffeine tolerance also depends on how much caffeine you take in daily.

To reap the benefits, you need a certain dose of caffeine. Most of the studies reviewed used intakes of 3–6mg/kg or 6–9mg/kg. Doses of less than 3mg (just over a cup of coffee for a 130-pound person) did not seem to produce performance benefits. Moderate doses of 5–7mg/kg (~300–400ml for a 130-pound person) seem to be the sweet spot. Additional benefits were not seen when athletes were given amounts >9mg/kg, so moderation is more in this case.

Anhydrous caffeine is more effective than coffee. Dosing of 3–6mg/kg of caffeine capsules has shown to provide a 24% improvement compared to no caffeine. In reality, few races give the opportunity to consume actual coffee during the effort. A 170-pound athlete would need roughly 4 cups of coffee or 6 Red Bulls to get the suggested performance dose which is unrealistic during a race. Athletes can instead turn to consuming sport-specific supplements such as gels, pills, chews or bars enhanced with small doses of caffeine.

Many athletes who are habitual caffeine users practice a pre-race withdrawal period to become sensitized to its effects. This seems to make sense; however, the practice holds no scientific merit. A study looking at a short term, 4–7 day abstention period found no difference in the gains achieved by consuming caffeine on race day compared to habitual users who did not abstain. This practice was actually contraindicated in research due to caffeine withdrawal effects (headaches, irritability, etc.) adding to excessive stress and disrupting normal patterns before an important race. Increasing sensitivity can also come with upping the potential negative effects on race day including excessive gastric stimulation. Remember: There is a high amount of individual variation in habitual caffeine consumption, effects and tolerance. Knowing your own body is vital to success.

Like anything athletes to do perform well, caffeine consumption should be a thoroughly thought out, well-practiced part of a training and nutrition plan. This includes assessing your normal daily caffeine intake, current training status, caffeine tolerance, preferred intake and timing schedule.

Your plan should consist of how much caffeine you are planning to take (‘x’mg/kg), what those sources will be (gels, bars, liquids, chews, pills) and when you will ingest these items throughout the race. This should be seamlessly integrated into your nutrition plan. For example, if you’re already consuming 2 gels/hour, you do not need to change anything except whether or not those gels contain caffeine. Figuring out that step brings us to timing. Just like everything in sports nutrition, timing is key. A common mistake athletes make is waiting until the end of a race, when they are really fatiguing to consume caffeine. However it takes roughly 30–45 minutes for caffeine to take effect, meaning it is unlikely to provide a benefit if taken at the start of a 5K or only in the final miles of an Ironman. To reap the full benefits, start caffeine 2 hours prior to the event for gastric effects to take place, another dose at the start line, and then space whatever caffeine you have left throughout the event.

Caffeine taken post-race, along with carbohydrates and protein, might increase the body’s recovery rate, however, this practice is generally ill-advised as the adverse effects of this late dose of caffeine on sleep habits are seen to outweigh the potential benefit.

Of course, potential benefits come with potential downsides. Caffeine consumption can promote sleeping problems, restlessness, anxiety, high heart rate and urine production. Many of these issues are personal and vary highly from individual to individual, making specific guidelines difficult to advise. Most athletes are concerned about the diuretic effect, which has been shown to be negatable and not an actual risk, just a popular myth.

Caffeine can be an extremely effective way to boost performance if taken at a dose your body can handle and provided at the right time during the effort. Special attention should be paid to learning your individual caffeine habits in and out of training to develop a protocol that is right for you.

Studies reference:

•  Zhang, et al. Caffeine and diuresis during rest and exercise: A meta-analysis. J Sci Med Sport. 2015 Sep; 18(5): 569-574
• O’Rourke et al. Caffeine has a small effect on 5-km running performance of well-trained and recreational runners. J Science and Med Sport. 2008 Apr;11(2):231-233.
• Goldstein et al. International Society of Sports Nutrition Position Stand: Caffeine and Performance. J International Society of Sports Nutrition. 2010; 7(5)
• Astorino et al. Increases in cycling performance in response to caffeine ingestion are repeatable. Nutr Research. 2012 Feb; 32(2): 78-84.
• Pickering, et al. What Should We Do About Habitual Caffeine Use in Athletes? J Sports Med. 2018.
• Astorino et al. Caffeine does not alter RPE or pain perception during intense exercise in active women. 2012 Oct; 59(2): 585-590.
• Arazi et al. The effects of different doses of caffeine on performance, rating of pain perception in teenager’s female karate athletes. Brazilian J Pharm Sci. 2010; 52(4).