As an athlete, it is important to be focused and perform your best.

Many athletes, as well as exercising individuals, have begun integrating a quick pick me up before their event to enhance performance. In fact, according to some research (3) sugar-free energy drinks have become staples to athletes and health buffs who are looking to get an extra boost to edge out their competition.

But do these drinks really work? Can an energy drink really make a difference in performance or is it all in our heads? And more importantly, is it safe?

Let’s take a quick look at some of the science:

In looking at sugar-free energy drinks, caffeine stands out as the most important performance enhancing ingredient (3). Which makes sense why this drink can be popular among athletes. Athletes need to feel energized and caffeine is reported to:

  • increase aerobic exercise performance (4, 10) and
  • lower our Rating of Perceived Exertion (4, 10)

(how hard we feel we need to push ourselves to perform adequately).

Definitely some beneficial effects. However, these effects are “dose-dependent”(5). This means that depending upon the dose of caffeine, you may or may not feel these benefits during your performance. Make sure you are aware of your body’s safe daily dose (12) of caffeine.

The table below addresses caffeine doses considered high and low:

Dose Level Amount
High > 3 mg∙kg-1 (~250 mg)
Low < 3 mg∙kg-1 (~250 mg)


Studies have found that high doses of caffeine can significantly improve run and exercise time-to-exhaustion performance (1, 6, 7, 8), aka the point in time where you can no longer sustain that initial high-intensity effort and begin to slow down or stop. However, high doses of caffeine can lead to negative health effects:

  • impaired glucose tolerance (2)
  • gastrointestinal irritation (9)
  • anxiety (11)
  • irritability (7)
  • nausea (7)
  • tachycardia (11)

So what about low doses?

A 2009 study (3) investigated low dose implementation among 17 physically active university students. Everyone was randomly given a drink, either sugar-free RedBull (2 mg∙kg-1 or ~147mg of caffeine) or a decaffeinated sugar-free placebo. Unaware of which drink they were given; subjects consumed the drink 1 hour before performing a controlled exercise test. This process was repeated several times over the course of a month and scientists measured: 1) run time-to-exhaustion, 2) rating of perceived exertion and 3) blood lactate.

The results showed 12 subjects ran approximately 1.4-2.1 minutes longer when using the sugar-free RedBull. However, 15 of the 19 subjects reported no change in their perceived exertion, meaning they did not feel their exercise experience was easier or harder when using either drink. In the end, the study did not find any significant difference in either performance variable.

If you take a glance at the graph below, you can see that there is no real difference between RedBull and the placebo. This is pretty much what you would expect based on the effects of caffeine alone since the dose used was less than that associated with enhanced performance.

sugar-free RedBull vs Placebo graph

What this study tells us is that sugar-free RedBull may give you an edge over the competition, but it is quite literally just an edge and not a significant one. Not only that, but it seems it may not even help you feel like your effort is easier – and let’s face it, “mind over matter” is a big deal in athletics.

So that’s that, yes?

Well let’s step out of this paper for a moment. Though this is a great study, we must always keep in mind this was one study – and they of course, cannot account for everything. Perhaps if the study was done over a longer period and/or used more subjects that lied in different age groups, the outcome may have been different. Both drinks used were sugar-free and lacked a carbohydrate element, and other studies have shown significantly enhanced physical performance with energy drinks that combine caffeine and carbohydrates (4, 10, 11), such as a regular RedBull (1).

What do I do now?

Know your ups and downs. If you’re an athlete, caffeine drinker or someone who likes to stay healthy, be aware of what you are consuming and how it makes you feel. Whether it’s RedBull (15) or otherwise, it is generally accepted that a safe dose (13, 14) of caffeine is 400 mg a day for a healthy adult. High doses (> 3 mg∙kg-1) of caffeine may give you that significant edge, but it can negatively affect your body. So be aware of how often and how much you are consuming. Monitoring how you and your body feels on your own can be difficult and bias, which may lead to inaccurate conclusions. Scientifically assessing your fatigue levels may be more beneficial and give more accuracy to how your body is reacting and “feeling” to your athletic routines. Sportavida’s goal is to help you understand and track your personal fatigue profile. If we can assess when and how our body is “fatiguing”, we can better manage it and not necessarily rely on artificial energy drinks to keep us going.

Thank you for reading! I hope you feel more informed and if you have any questions or comments, please feel free to give a shout out.





  1. Alford, C, Cox, H, and Wescott, R. The effects of Red Bull energy drink on human performance and mood. Amino Acids 21: 139–150, 2000.
  2. Battram, DS, Arthur, R, Weekes, A, and Graham, TE. The glucose intolerance induced by caffeinated coffee ingestion is less pronounced than that due to alkaloid caffeine in men. J Nutr 136: 1276–1280, 2006.
  3. Candow DC, Kleisinger AK, Grenier S, Dorsch KD (2009) Effect of sugar-free Red Bull energy drink on high-intensity run time-to-exhaustion in young adults. J Str Cond Res 23(4):1271–1275
  4. Cox, GR, Desbrow, B, Montgomery, PG, Anderson,ME, Bruce, CR, Theodore, AM, Martin, DT, Moquin, A, Roberts, A, Hawkley, JA, and Burke, LM. Effect of different protocols of caffeine intake onmetabolism and endurance performance. J Appl Physiol 93: 990–999, 2002.
  5. Crowe,MJ, Leicht, AS, and Spinks, WL. Physiological and cognitive responses to caffeine during repeated, high intensity exercise. Int J Sport Nutr Exerc Metab 16: 528–544, 2006.
  6. Forbes, SC, Candow, DG, Little, JP, Magnus, C, and Chilibeck, PD. Effect of Red Bull energy drink on repeated Wingate cycle performance and bench press muscular endurance. Int J Sports Nutr Exerc Metab 17: 433–444, 2007.
  7. Graham, TE. Caffeine and exercise: Metabolism, endurance and performance. Sports Med 31: 785–807, 2001.
  8. Graham, TE and Spriet, LL. Metabolic, catecholamine, and exercise performance responses to various doses of caffeine. J Appl Physiol 78: 867–874, 1995.
  9. Juliano, LM and Griffiths, RR. A critical review of caffeine withdrawal: Empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacol 176: 1–29, 2004.
  10. Kovacs, EM, Stegen, J, and Brouns, F. Effect of caffeinated drinks on substrate metabolism, caffeine excretion, and performance. J Appl Physiol 85: 709–715, 1998.
  11. Reissig, CJ, Strain, EC, and Griffiths, RR. Caffeinated energy drinks—A growing problem. Drug Alcohol Depend 99: 1–10, 2009.