Could Caffeine Help Improve Exercise and Performance


Caffeine is synonymous with a boost of energy, but what are the implications of consuming it? There’s no conclusive evidence as to its effect on exercise and performance, but we’ve done our best to shed light on this important topic.

What is caffeine and how does it make us feel more energetic?

“Caffeine is a unique substance in that it can be found in common foods, drugs, or dietary supplements. It occurs naturally in the leaves, nuts, and seeds of many plants, or it can be synthesized in the laboratory … Caffeine’s mechanism of action is thought to be related to the compound adenosine, which is present in all cells in the body. Adenosine aids the body in falling asleep by blunting communication between nerve cells and by dilating the blood vessels to permit increased oxygen flow. Caffeine and adenosine compete for the same receptors in the brain, therefore, reduced adenosine binding caused by increased caffeine availability results in more alertness.”

What are the potential benefits of caffeine?

1. Delay fatigue

2. Lower perceived exertion

3. Increase focus

4. Increase energy

5. Increase fat mobilisation

6. Increase thermogenesis

7. Reduce tiredness

8. Preserve muscle glycogen stores

What are the potential side effects of caffeine?

1. Elevated heart rate

2. Elevated blood pressure

3. Headaches

4. Jitteriness

5. Dizziness

6. Insomnia or sleep disruption

7. Gastrointestinal distress

8. Adrenal fatigue

What is the recommended dose?

There’s no magic number as there are too many variables. A few questions to consider – are you an acute or habitual user? What is your sensitivity to caffeine? In which form is it being consumed?

“The major dietary sources [of caffeine] are soft drinks, tea, and coffee, which contain approximately 30 to 250 mg per serving … In studies evaluating activities lasting at least an hour, intakes as small as 1 to 2 mg/kg body weight have been shown to improve performance … most of the research data examining dose-response effects support a ceiling somewhere between 5 and 6 mg/kg body weight, where no further increase in performance is reported with higher doses”

Depending on the individual tolerance and sensitivity we would suggest starting at lower dose of 1 to 2 mg/kg body weight.

“Caffeine peaks between 30 and 75 minutes after ingestion and has a half-life of 4 to 5 hours. Therefore, caffeine ingestion should be timed to coincide with the particular activity.”

How does caffeine affect exercise and performance?

Although some studies have found caffeine to have a positive effect on exercise and performance, science hasn’t yet shown that to be definitively true.

With regards to endurance training:

“From a small pool of studies, it seems that caffeine ingestion does not enhance performance in endurance activities lasting less than 20 minutes. On the other hand, caffeine has been shown to enhance performance in longer exercise bouts by increasing work output and time to exhaustion in studies examining swimming, running, and cycling. The caffeine doses in most of these studies ranged from 2 to 6 mg/kg body weight.”

Another study reports, “In 2009, Matthew Ganio, an exercise physiologist at the University of Arkansas Department of Health, Human Performance and Recreation, led a review of 21 papers on the effect of caffeine on endurance athletes. The studies included tests ranging from 15 minutes to two hours.

The results varied between the studies, Ganio et al. reported, but the mean improvement in performance was 3.2 percent. Ganio reported a high degree of variability among studies, with additional research required for explanation … As Ganio’s review suggested, what’s not clear is exactly how caffeine helps endurance athletes.”

With regards to strength training:

“Research in anaerobic activities is equivocal. Some studies report improved sprint cycle performance, running speeds, and peak power outputs, with caffeine use, whereas others do not. Similarly, two studies reported that doses of 6 mg/kg body weight improved sprint speed, power, and accuracy in male team sports. More research is needed to determine if caffeine is indeed ergogenic during these types of activities, which specific activities and intensities caffeine may enhance, and the doses that may produce the desired effects … Some studies examining the effects of caffeine on resistance training performance report increased maximal strength, number of repetitions, total volume of exercise, and reduction in pain and force loss. One study did report increased heart rate and blood pressure with caffeine ingestion before resistance training”

Another study reports, “Beardsley was unable to find definitive evidence that caffeine improves maximal efforts during resistance training or one-rep-max efforts. He looked at four studies, and just one found caffeine had a very small positive impact on a max-effort strength test … Beardsley looked at 11 different studies focusing on multiple reps—sometimes to failure, some in the 10-to-12-rep-max range—and concluded, “It is possible that caffeine is effective for improving repetition effort performance during resistance-training, but not all studies support this conclusion.” 

A lot more research is needed before we can say with certainty what caffeine’s effect is on exercise and performance, but at this present moment it appears that caffeine may have an impact for some and not for others.

We would advise individuals wishing to try caffeine as means to improve performance to do so during practice or training. For habitual users who wish to discontinue caffeine use and then reintroduce it to improve sensitivity, we would suggest gradually reducing their intake instead of completely abstaining.

Our conclusion

Caffeine may possess performance-enhancing benefits, but because of the variability of the results from the research conducted thus far, it is difficult to draw absolute conclusions.

We would suggest identifying and consuming the smallest amount of caffeine that will produce the desired performance benefit with minimal side effects. Minimal doses will also help reduce the risk of forming a dependency or experiencing withdrawal symptoms upon cessation.

If you don’t ordinarily consume caffeine, we would caution against using it solely as a performance enhancer at this point in time.

Thank you for reading this post

We truly hope that you found this post valuable. If you have any questions or if you’d like to work with one of our experienced personal trainers, please feel free to contact us


1) Kruskall, Laura J. et al. (2009) ‘Caffeine and Exercise Performance: What’s All the Buzz About?’, ACSM Health & Fitness Journal, November-December 2009. Available at: (Accessed: 6 August 2020)

2) Achauer, H. (2017) ‘Caffeine: Pre-Workout Placebo?’, CrossFit Journal, 5 July. Available at: (Accessed: 6 August 2020)

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.


    As Personal Trainer’s in Surrey & South London, we are excited to help you with
    5 fundamental fitness and lifestyle steps.
    • This field is for validation purposes and should be left unchanged.
  • Latest Posts

  • Archives

  • Categories