Can energy drinks improve our endurance performance?

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Energy drinks are well known for boosting energy and alertness. But do energy drinks improve our endurance performance?

A traditional energy drink is created from sugars, typically sucrose and glucose, caffeine and taurine. Other ingredients may include glucuronolactone, inositol, and B vitamins. (Britishsoftdrinksassociation, 2016). All these ingredients act as stimulants. Therefore, any drink that contains high levels of these ingredients can be classed as an energy drink.  

Ingredients in energy drinks and their effects

  • Ephedrine – affects our central nervous system, increases mental agility and decreases the feeling of fatigue (Seppala, 2019) 
  • Taurine – An amino acid that that regulates heart beat and muscle contractions  
  • Ginseng – reduces stress and boosts energy 
  • B-vitamins – these tend to help with converting sugar into energy  
  • Inositol- helps with delivering signals between body cells (Watson, 2019) 
  • Glucuronolactone –  combined with caffeine it supplied energy 

What do energy drinks do within our body? 

Energy drinks contain mostly caffeine, and caffeine blocks the effects of adenosine. This is a chemical found in our brain that signals when our body is tired. In other words, adenosine alerts you that it is time to go to sleep.  

When adenosine gets blocked, our body enters into the ‘fight or flight’ mode by releasing adrenaline as the body thinks there is an emergency somewhere. Adrenaline will then make your heart beat faster and your eyes to dilate. Adrenaline will also cause your liver to release extra sugar into the blood stream to support the energy ‘required’. All of those responses make you feel like you have more energy.  

Can energy drinks improve our endurance performance? 

Some fitness experts may disagree, but some research proves the effectiveness of energy drinks on our performance. This may due to the fact that more research is required because some studies show effects and other studies fail to show significant effects.

One study done by Ivy et al (2009) looked into the effects of drinking an energy drink one hour before cycling. The participants had to fast for 12-hours before drinking either 500ml of flavoured juice or 500ml (160mg caffeine) of Red bull Energy Drink. For those who are not familiar with fasting, it would simply mean that they haven’t eaten anything for those 12-hours. This study demonstrated that those who drank Red Bull managed to complete the cycling trial faster without any increase in perceived fatigue than those who drank flavoured juice. This study has shown positive effects of energy drink on endurance performance.  

More energy drink case studies

Another study conducted by Cox et al (2002) included 12 participants. They were given either:

  • 6mg of caffeine per kg of their bodyweight 1-hour before a 2-hour steady cycle
  • 6 x 1mg per kg of their bodyweight of caffeine every 20 minutes throughout the 2-hour steady cycle
  • 2 x 5ml per 1 kg bodyweight of Coca-Cola in 100-120minutes of the steady cycle exercise.

This study found that it took less time to complete the exercise by 3.4% (6mg of caffeine), and a reduction by 3.1% for people who consumed 1mg of caffeine throughout exercise and Coca-Cola. This study, again, shows that the caffeinated drink sped up the time it took to complete the steady cycling trial.  

However, there was a second part of this study where 8 participants received 3 x 5ml per 1kg of their bodyweight of different Coca-Cola drinks during the last 40 minutes of the steady cycle trial. Some Cola drinks were decaffeinated and some were caffeinated but of course, the amount of caffeine was a lot lower compared to an energy drink. This part of the study showed that replacing energy drinks with Cola was as equally effective.  So do energy drinks improve our endurance and fitness levels?

More trials

In 2006, Bridge & Jones conducted a study into the effects of caffeine ingestion one hour prior to a 8km run. This study showed a mild increase of 1.2% improvement in performance compared to people who were not ingested with caffeine.  

On the other side, a study conducted by Astorio et al (2012) looked into the effects of Red Bull on sprint performance in women athletes and it failed to deliver any significant improvements. Another study, done by Hunter et al (2002) looked into the effects of caffeine ingestion on endurance performance during a 100km cycling trial. This is another study that failed to deliver positive effects.  

Therefore, energy drinks may improve your endurance performance in certain sports or when they are taken at the right times, like 1 hour before exercise. In addition, as energy drinks make you feel less tired you will likely be able to exert more power during weight training. However, as you’ve seen the trials are inconclusive. You should maybe only use energy drinks if ou are tired and need a boost of energy to make your workout productive.

Are energy drinks harmful to our health?  

Caffeine in normal doses is not harmful, approximately 400mg of caffeine per day is considered to be safe for healthy adults. That’s approximately 2-3 small cans of red bull. But, some energy drinks contain as much as 160mg to 500mg of caffeine so please read the labels carefully (Daniel, 2012).  However, 750-1000mg of caffeine is a significant amount and can cause some damage to an average adult. It should be noted that ‘average’ or ‘healthy’ adult is a person of good health, but caffeine can become harmful at much lower doses depending on your age, weight, medical conditions and/or drug abuse. Consequently, the legal age to drink energy drinks was raised to age 16 (National Center for Complementary and Integrative Health, 2018).  

It should be noted that, high amounts of caffeine may cause serious heart and blood vessel problems which can lead to increased risk of cardiac arrest, heart rhythm disturbances, increases to blood pressure and heart rate. As a result, you should limit your caffeine intake during pregnancy as it can damage the child’s cardiovascular and nervous system. In addition, other issues that may occur are anxiety, sleep problems, digestive problems ((National Center for Complementary and Integrative Health, 2018). 

Another thing we wish to mention is, if you enjoy having an alcoholic drink with an energy drink it can blur or delay your ability to recognise when you are drunk despite the fact that your coordination and so on would be impaired (National Center for Complementary and Integrative Health, 2018).  


In conclusion, does caffeine improve endurance performance? It is difficult to make a conclusion on this one. We believe the reason is due to some people are more sensitive to caffeine compared to others. Whereas, some people may simply react better to caffeine than others. So if it works or not, you need to try it out for yourself.  

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Association, B. (2019). Information on Energy Drinks. [online] Available at: [Accessed 17 Oct. 2019]. 

Astorino, T., Matera, A., Basinger, J., Evans, M., Schurman, T. and Marquez, R. (2011). Effects of red bull energy drink on repeated sprint performance in women athletes. Amino Acids, 42(5), pp.1803-1808. 

Bridge, C. and Jones, M. (2006). The effect of caffeine ingestion on 8 km run performance in a field setting. Journal of Sports Sciences, [online] 24(4), pp.433-439. Available at: [Accessed 7 Oct. 2019]. 

Cox, G., Desbrow, B., Montgomery, P., Anderson, M., Bruce, C., Macrides, T., Martin, D., Moquin, A., Roberts, A., Hawley, J. and Burke, L. (2002). Effect of different protocols of caffeine intake on metabolism and endurance performance. Journal of Applied Physiology, [online] 93(3), pp.990-999. Available at: [Accessed 5 Oct. 2019]. 

Daniel, K. (2012). “No Bull” Right to Know: How Much Caffeine is in Monster Drinks? – The Weston A. Price Foundation. [online] The Weston A. Price Foundation. Available at: [Accessed 17 Oct. 2019]. 

Hunter, A., St Clair, G., Collins, M., Lambert, M. and Noakes, T. (2002). Caffeine ingestion does not alter performance during a 100-km cycling time-trial performance. [online] 12(4). Available at: [Accessed 17 Oct. 2019]. 

Ivy, J., Kammer, L., Ding, Z., Wang, B., Bernard, J., Liao, Y. and Hwang, J. (2009). Improved Cycling Time-Trial Performance after Ingestion of a Caffeine Energy Drink. International Journal of Sport Nutrition and Exercise Metabolism, [online] 19(1), pp.61-78. Available at: [Accessed 7 Oct. 2019]. 

Mayo, C. (2019). Caffeine: How much is too much?. [online] Mayo Clinic. Available at: [Accessed 17 Oct. 2019]. 

NCCIH. (2019). Energy Drinks. [online] Available at: [Accessed 17 Oct. 2019]. 

Seppala, T. (2018). Ephedrine and Related Substances. [online] Available at: [Accessed 2 Oct. 2019]. 

Watson, S. (2019). How Do Energy Drinks Work?. [online] HowStuffWorks. Available at: [Accessed 17 Oct. 2019]. 


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