What is Caffeine and How Does It Work?

Caffeine is one of the most consumed natural pharmacologic agents. Whether you’re consuming it through coffee, tea, energy drinks, pre-workout supplements, or even just caffeine pills, caffeine tends to be everywhere. It’s so prevalent that 9 out of 10 men and women consume around 240mg every day. So many people consume and use caffeine that the International Olympic Committee actually removed caffeine from their banned substance list.

So what is caffeine, specifically? Caffeine is a natural drug that is classified as a central nervous system (CNS) stimulant that can help keep us awake, alert, and keep going when you’re tired or ready to lay down. Caffeine is able to do this because it acts opposite to a CNS depressant that is found in our bodies, adenosine, and both caffeine and adenosine look very similar to each other. Adenosine promotes sleep and slows down nerve activity in our brains, and about every hour or so the levels of adenosine in the brain rise.

With caffeine inhibiting adenosines ability to attach to their receptors in the brain, the pituitary gland observes this increased activity and then triggers the adrenal glands to produce epinephrine. This is why we feel more awake, and also why some people can suffer from jitters, nervousness, an elevated heartrate, and even disrupted sleep (Nichols, 2016).

Caffeine Dosage for Sports Performance

A lot of the research into caffeine and its effects on sports performance has been focused on the moderate to high doses of caffeine, usually ranging from 5 to 13 milligrams per kilogram of body mass (mg/kg body mass) (Spriet, 2014). Lower doses of caffeine, which is defined as less than 3mg/kg body mass, is starting to be studied and utilized a lot more in sports now because athletes are still receiving the increased alertness, mood, and cognitive processes while not experience all of the side effects, if any, as well as the whole-body responses (Spriet, 2014).

While a low dose of caffeine may work for some, others may not reap the benefits from a low dose and may need a little more caffeine. This is where a good majority of the research has been done. In a randomized and double-blind study, researchers found that a dose of 9mg/kg body mass 1 hour before exercise that endurance times were increased during running and cycling, pushing their exhaustion times back and allowing their participants to exercise at a high intensity for a longer time (T.E. Graham, 1991).

How to Take Caffeine for Improved Performance

Speaking towards weightlifting specifically, the proper caffeine dose is going to vary from person to person, and what works for one may not work for another. That being said, dosing for a team sport such as soccer or football will most likely be different as well.

In order to determine the proper dose for someone, it’s a little tricky and can take some time to figure out how much caffeine you should be taking. Caffeine has been effective for enhancing performance in low to moderate dosages, usually around 3-6mg/kg body mass and does not further enhance performance when consumed in higher dosages, or more than 9mg/kg body mass (Erica R. Goldstein, 2009). The smallest dose where you can start to feel or notice improvements in your performance should be the ideal amount to take before your workouts. I say this because recovery and repair from workouts is where improvements are made, and if you’re drinking too much caffeine to the point where your hormones and adrenal gland are out of whack, your sleep and recovery from your workouts will be impacted as well.

Now, in order to figure out the proper dose for yourself, convert your body into kilograms. If you don’t know how to do this, just divide your bodyweight in pounds by 2.2. This will give you your bodyweight in kilograms, then multiply that number by your decided dose. If it’s your first time, start with 3mg/kg body mass and slowly work up to a higher dose if needed. If 3mg/kg body mass doesn’t work, go to 6mg/kg body mass, and then 9mg/kg body mass if needed.

-Tyler Giery BS,CPT


  • Erica R. Goldstein, T. Z. (2009). Internation Society of Sports Nutrition Position Stand: Caffeine and Performance. Journal of the International Society of Sports Nutrition.
  • Nichols, H. (2016, November 10). Caffeine: All You Need To Know. Retrieved from Medical News Today: https://www.medicalnewstoday.com/articles/285194.php
  • Spriet, L. L. (2014). Exercise and Sport Performance with Low Doses of Caffeine. National Center for Biotechnology Information, 175-184.
  • T.E. Graham, L. S. (1991). Performance and metabolic responses to a high caffeine dose during prolonged exercise. Journal of Appllied Physiology, 2292-2298.