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Caffeine is a drug whose appeal shows no sign of slowing. It’s a fix we’re legally allowed to enjoy, and it’s a stimulant for our central nervous system that we’re legally allowed to use to try and enhance our sporting performance. However, Olympic committees are actually debating whether or not caffeine should be tested prior to the Olympic Games because of its recognized ergogenic effects.

An ergogenic aid, or performance enhancer, is anything that gives you a mental or physical edge while exercising or competing. This can range from caffeine and sports drinks to the illegal stuff (which of course NONE of you will be familiar with).

It seems there are three main ways in which caffeine provides this ergogenic effect:

  1. The metabolic theory suggests that caffeine provides improved endurance due to an increased utilization of fat as a fuel and a sparing effect on carbohydrate utilization.

  2. Secondly, caffeine may increase the calcium content of skeletal muscle and enhance the strength of muscle contraction.

  3. Finally, caffeine is known to combat fatigue by having an action on the central nervous system, lowering the perception of effort, allowing you to keep going at the same pace for longer, or being able to increase your pace as you’re perceiving the effort to be less.

This last point is the one that current research is focused on – the effect caffeine has on the central nervous system, as it’s generally considered that this is its main performance-enhancing aspect.

What are the recommended doses of caffeine? Here opinion is definitely divided. suggest a daily dose could be between 3-6mg per kilogram of body weight (eg if your weight is 60kg, you’d need a dose of 180-360mg). They advise starting with 3mg if you’re already a habitual consumer of caffeine, but if not, then they suggest starting with as little as 1mg per kg of body weight. They add that more experienced runners can try with higher doses, up to 6mg/kg body weight - however increasing the amount of caffeine beyond 3mg per kilogram of your body weight does not necessarily mean further performance gains (er, so what’s the point then?!) are more cautious and they flag that the 3-6mg per kg of body weight quota is not recommended for a daily routine, but rather an occasional big race or marathon. They advise against caffeine pills and instead advocate getting caffeine naturally through certain foods and drinks (AGREE ENTIRELY).

It’s worth flagging here that the effects of caffeine differ depending on whether you are a responder or a non-responder. If you are an individual who can drink a cup of coffee late at night and still sleep like a baby, you are a non-responder. In other words caffeine has no effect on you or your nervous system. If the opposite is true, where you would be up all night tossing and turning, then you are a responder.

The different ways caffeine affects different people means that it’s very hard to dictate when caffeine should be used, but it’s generally accepted that elevated levels of caffeine will start to appear in the blood stream between 15-45 minutes after consumption and will be at peak concentration at approximately 60 minutes.

Some athletes choose to can the caffeine a week or more before a major event, to ensure maximum impact when they come back to it. But this is as disputed as the controversy over whether habitual use of caffeine leads to decreased effectiveness of a caffeine supplement during an event / training. As I’m typing, a FB post has just popped up from the boy Coomber about just this…

“If you have caffeine in your diet all the time, you don't get much of a boost pre workout. You might get a little boost if you take a bigger dose, but it's a slippery slope. It's just like many drugs, the more you take over time, the more you need to get the same effect”.

He says ‘cut down’ in one breath, but in the next he’s talking about (slash passively advertising) the caffeine tabs that his company (Awesome Supplements) make and sell. It’s at this point that I block my ears to the boy Coomber…is not selling caffeine tabs in an easy to consume format encouraging consumption of the drug rather than limiting it??

Popping a caffeine tab is crazy in my mind, instead I’d follow the example of our very own Will Holme (worthy of far greater acclaim than my previous reference). He’s pro caffeine as a pre-workout – but rather than reaching for a supplement, he just swigs an espresso with a smidge of honey and away he goes. You gotta give it to him, the boy’s got style…(and energy, is this his secret, finally outed?!)

But if coffee’s not your thang (which it’s not for me), then there are plenty of other sources of caffeine:

Instant coffee (250ml) - 50-70mg

  • Filter coffee (250ml) - 120mg

  • Tea (250ml) - 15-70mg

  • Coke (330ml/500ml) - 43mg/65mg

  • Hot chocolate - 8-15mg

  • Caffeinated sports gel - 25mg-100mg (check label)

  • Caffeine tablets - 50g per tablet but check the label

My fix comes from green tea rather than regular tea / coffee. There’s less caffeine, but still enough to keep me annoyingly buzzy and frighteningly addicted (and consequently very, very angry when I visit someone who doesn’t have a bag to offer me. GGGGGGGRRRRRRRRR). For my own interest, rather than yours, I did a quick comparison of the caffeine content of green vs regular tea…findings as follows:

Generic black tea:

1 min brew: 19mg caffeine

3 min brew: 28mg caffeine

5 min brew: 31mg caffeine

Generic green tea:

1 min brew: 9mg

3 min brew: 18mg

5 min brew: 21mg

Also worth flagging here that 2 cups of regular tea is equal (on average) to 1 cup of coffee. There are 20mg of caffeine in your average 100g of brewed tea compared to 40mg in the same amount of black filter coffee. But the type of tea, as well as the brewing time makes a difference.

Being aware of the quantities you’re consuming can of course help ensure you don’t overdo the caffeine…something to watch out for because too much caffeine can definitely have side effects.

The list of these is long, and it includes: headaches, jitters, insomnia, diuresis, nausea, muscle tremors, impaired coordination, increased heart rate, anxiety. You’ve got to weigh up if the side effects outweigh the benefits.

NB For pregnant women the NHS recommends consuming no more than 200mg of caffeine per day from all sources.

To conclude, I’d say this legal fix, has got its ups (pardon the pun) and its downs. But in my mind it’s hugely over-consumed. It’s fashionable, it’s habitual, it’s a crutch to many people. To enjoy a coffee is one thing. But to depend on it, especially for improved sporting performance, is quite another.

Rather than always reaching for the caffeine, maybe consider other areas first. What’s your training plan looking like? Are you over doing it? Is your diet right – are you taking on enough calories for the energy you’re expending? Are you well hydrated? Are you getting enough sleep? Caffeine can be used as an occasional boost, sure, but there are many other more important areas to focus on to optimize performance before popping a ‘perk pill’!

That’s all from me, the puritanical preacher, for a while. I shall be back in the New Year, so please do feel free to send through (expensive Christmas gifts, nothing homemade or worst still hand-crafted and) any topics you’d like covered in 2017.

Eat lots. Exercise more.


References and quotations:, Ruth McKean Asics Pro Team Nutritionist

International Society of Sports Nutrition

Scienceinsport, Ted Munson, Performance Nutritionist

Ben Coomber

Brian Mac, sports coach


I am not a dietician or a nutritionist, and make no claims to the contrary. What is written on this site should not be taken as fact or advice. It is merely an opinion blog.

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