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Pre-Workout Caffeine | Benefits & Side Effects

Pre-Workout Caffeine | Benefits & Side Effects
Claire Muszalski
Registered Dietitian2 years ago
View Claire Muszalski's profile
When it comes to providing a quick energy boost, caffeine is second to none. It’s the key ingredient in many energy drinks, pre-workouts and stimulant supplements.When it comes to training, how effective is pre workout caffeine? The answer: caffeine affects people in different ways, so what works for one person may not work for you. Let’s get the details...Jump to:

What are the Benefits of Pre-workout Caffeine?

Caffeine works by promoting excitability within the spinal cord, and by muscle fibre recruitment.1Furthermore, it decreases our perception of fatigue and muscular pain. This means that it can provide us with a whole host of benefits.1 

Improved alertness

Caffeine causes the release of dopamine, a chemical in the brain which stimulates the areas of your grey matter.2 Dopamine is responsible for your alertness, as well as pleasure, making it known as the “feel good” hormone. This increase in dopamine may enhance problem-solving abilities, making you feel more ‘on the ball’.In addition to increasing dopamine levels, caffeine also blocks receptors for adenosine, the signalling molecule that promotes sleep in the body.1 With more dopamine and less adenosine, your brain and body feel more awake and alert. 

Relieves muscular pain

Caffeine is one of the main ingredients in many pain relievers. It’s been shown that caffeine can help alleviate post-workout pain and muscle soreness, meaning you’ll be able to hit the gym just as hard each day.This makes caffeine an ideal supplement to take pre workout. 

Improves speed and endurance

Consuming pre workout caffeine before a workout can improve both your speed and stamina while making your workout seem easier and less strenuous!1,3 

Speeds up heart rate

Since caffeine has an effect on your central nervous system, it could help you by increasing your heart rate and breathing rate.4 This means you can supply your muscles with more oxygen, allowing them to aerobically respire more successfully, increasing output. 

Replenishes glycogen stores

Caffeine, when consumed with carbohydrates, has been shown to replenish muscle glycogen stores quickly after exercise.5

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Side Effects of Caffeine

As with most things, caffeine isn’t all good; there are some ‘side effects’, or negatives which it can present.  


Caffeine has been shown to lead to dehydration, as it can have a slight diuretic effect. Therefore, if you’re consuming reasonably high levels of caffeine throughout the day, it’s recommended to increase your water intake to reduce the risk of dehydration. If you take pre-workout caffeine, then you should definitely ensure you keep drinking water throughout your workout. 



Since caffeine is a powerful stimulant, it’s fairly evident that it could present some adverse side effects when it comes to the quality of sleep. Depending on the individual, the results can vary. You should therefore be careful when taking pre-workout caffeine in the evening; perhaps consider our stimulant free pre workout supplement The Pump.Some may not be hindered by caffeine when it comes to sleeping, but for others, it could be an issue. You should moderate your intake if you recognise that it affects you negatively and do not drink caffeinated drinks in the evening or before you go to bed.  


Caffeine can be very addictive – withdrawal from caffeine can present side effects such as headaches, anxiety and cravings. These can be prevented by gradually weaning yourself off, lowering your dosage.  


The recommended daily dosage for an average adult should not exceed 400mg.6 This level has been found to be generally safe in healthy individuals, but there are many groups in which caffeine should be avoided (pregnancy/lactation, children, those with underlying health conditions, etc). Based on height and weight a lower dosage might be more appropriate for you. Below are the caffeine contents of several popular drinks and foods: Espresso – 100mgInstant coffee – 65-100mgEnergy drink – 80mgDiet Coke – 45mgTea – 30mgDark chocolate (30g) – 20mgGreen tea – 15mg


Pre-Workout Caffeine

Caffeine is recommended for having as a pre-workout, as it can provide a brilliant energy boost to help push you through your workout. Ensure you do not take it too late in the day, so it does not hinder your sleep. Caffeine can be purchased in supplement form as tablets, or in powders. It is also a key ingredient in most pre-workouts. If you find that you cannot tolerate caffeine, then there are also some pre-workouts out there which are caffeine-free, such as The Pump.


Take Home Message

Caffeine can be a potent supplement, which is fantastic for taking pre-workout and enhancing your training as well as giving you more energy throughout your everyday life.However, do consider the above side effects which you could experience if you exceed the recommended dose. If you do feel you’re experiencing any of these, consult your GP.
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Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you're concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

  1. Goldstein, E. R., Ziegenfuss, T., Kalman, D., Kreider, R., Campbell, B., Wilborn, C., … & Antonio, J. (2010). International society of sports nutrition position stand: caffeine and performance. Journal of the International Society of Sports Nutrition7(1), 1-15. 
  2. Cauli, O., & Morelli, M. (2005). Caffeine and the dopaminergic system. Behavioural pharmacology16(2), 63–77. 
  3. Wiles JD, Bird SR, Riley M: Effect of caffeinated coffee on running speed, respiratory factors, blood lactate and perceived exertion during 1500-m treadmill running. Br J Sp Med. 1992, 26: 116-20. 10.1136/bjsm.26.2.116. 
  4. Rauh, R., Burkert, M., Siepmann, M., & Mueck‐Weymann, M. (2006). Acute effects of caffeine on heart rate variability in habitual caffeine consumers. Clinical physiology and functional imaging26(3), 163-166. 
  5. Pedersen DJ, Lessard SJ, Coffey VG, Churchley EG, Wootton AM, Ng T, Watt MJ, Hawley JA: High rate of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine. J Appl Physiol. 2008, 105: 7-13. 10.1152/japplphysiol.01121.2007. 
  6. Temple, J. L., Bernard, C., Lipshultz, S. E., Czachor, J. D., Westphal, J. A., & Mestre, M. A. (2017). The safety of ingested caffeine: a comprehensive review. Frontiers in psychiatry8, 80. 
Claire Muszalski
Registered Dietitian
View Claire Muszalski's profile

Claire is a Registered Dietitian through the Academy of Nutrition and Dietetics and a board-certified Health and Wellness Coach through the International Consortium for Health and Wellness Coaching. She has a Bachelor of Science in Biology and a Master’s degree in Clinical Dietetics and Nutrition from the University of Pittsburgh.

Talking and writing about food and fitness is at the heart of Claire’s ethos as she loves to use her experience to help others meet their health and wellness goals.

Claire is also a certified indoor cycling instructor and loves the mental and physical boost she gets from regular runs and yoga classes. When she’s not keeping fit herself, she’s cheering on her hometown’s sports teams in Pittsburgh, or cooking for her family in the kitchen.

Find out more about Claire’s experience here.