Author: Dana Ryan – Ph.D., M.A., MBA, Director, Sports Performance & Education


Caffeine is one of the most well-studied ergogenic aids, which are substances that help support athletic performance and physical activity.

Many athletes use caffeine to boost performance, especially before working out, training, or playing sports. In general, most people can benefit from taking caffeine before exercise.


Caffeine Can Improve Training and Exercise

Caffeine works by stimulating the central nervous system, heart, muscles, and the centres that control blood pressure*. As a stimulant, it facilitates the body’s ability to use fat for fuel. For this reason, caffeine may help to extend endurance during strenuous exercise.

It also reduces the perception of fatigue, helping you stay motivated through sustained activities. A moderate amount of caffeine, taken an hour before strenuous training or a competition, has been found to significantly increase performance as compared to a placebo, with the athletes affected by minimal side effects**. That said, it’s no wonder that caffeine use in sports is very common.


Caffeine Enhances Mental Focus and Alertness

Caffeine has also been shown to enhance mental focus, which can be extremely beneficial pre-workout. Caffeine stimulates the brain and contributes to clearer thinking and greater concentration. Whether it is getting in the zone or making quick game-time decisions, caffeine can be very effective when playing competitive sports.


Best Sources of Caffeine

Caffeine is found in many foods and beverages and can be obtained from a variety of sources. Most commonly, people will get caffeine from coffee, tea, or a pre-workout supplement that may contain an effective source of caffeine like guarana seed. Keep in mind the calories when you consume caffeinated beverages like soda or energy drinks – they can add up quickly if you’re not careful.

People’s sensitivity to caffeine can vary. Some will metabolise caffeine quickly, while others will metabolise it more slowly; some will show greater sensitivity to the stimulating effects of caffeine, while others need higher amounts to feel an effect***.

If you are just starting to use caffeine, it is best to start small and then add more if you need it. Avoid more than 200 mg of caffeine in one serving (there is about 100 mg caffeine in a standard 225 mL coffee); and no more than 400 mg in one day.

For maximum effectiveness, try consuming caffeine 15-30 minutes before starting a workout.



* Dunford M, Coleman EJ. Ergogenic aids, dietary supplements, and exercise. In: Rosenbloom CA, Coleman EJ, eds. Sports Nutrition: A Practice Manual for Professionals. 5th ed. Chicago, IL: Academy of Nutrition and Dietetics; 2012:128.

** Spriet L. Exercise and Sport Performance with Low Doses of Caffeine. Sports Med. 2014; 44(Suppl 2): 175–184.

***Nehlig A. (2018) Inter-individual differences in caffeine metabolism and factors driving caffeine consumption. Pharmacol Rev. 70(2):384–41.