Pre-Workout Caffeine | Benefits & Side Effects

When it comes to providing a quick energy boost, caffeine is second to none. It is the key ingredient in many energy drinks, pre-workouts and stimulant supplements.

When it comes to training, how effective really is caffeine?

The answer: caffeine affects people in different ways, so what works for one person may not work for you! Let’s discuss further…

Benefits of Caffeine

Caffeine works by promoting excitability within the spinal cord, and by muscle fibre recruitment.

Furthermore, it decreases our perception of fatigue and muscular pain. This means that it can provide us with a whole host of benefits.


Pre-Workout Caffeine | How Caffeine Affects Exercise: Benefits & Side Effects

 Improved alertness

Caffeine causes the release of dopamine, a chemical in the brain which stimulates the areas of your grey matter. It’s responsible for your alertness, as well as pleasure. This increase in dopamine may enhance problem-solving abilities, making you feel more ‘on the ball’.

 Relieves muscular pain

Caffeine is one of the main ingredients in many pain relievers. It has been shown that caffeine can help alleviate post-workout pain and muscle soreness, meaning you will be able to hit the gym just as hard each day.

 Improves speed and endurance

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

 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. 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.

Side Effects

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 are consuming reasonably high levels of caffeine throughout the day, it is recommended to increase your liquid intake to reduce the risk of dehydration.


Since caffeine is a powerful stimulant, it is 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.

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 is a drug – 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.

Pre-Workout Caffeine | How Caffeine Affects Exercise: Benefits & Side Effects

Below are the caffeine contents of several popular drinks and foods:

Espresso – 100mg

Instant coffee – 65-100mg

Energy drink – 80mg

Diet coke – 45mg

Tea – 30mg

Dark chocolate (30g) – 20mg

Green 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.

Take Home Message

Caffeine can be a potent supplement, which is fantastic for 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!



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.



Writer and expert

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