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Forget Caffeine Supplements, Coffee Will Do?

Do I need to stop drinking coffee to get the most exercise performance impact out of my caffeine supplements?

This is a common question. People think they need to stop having coffee to make themselves more sensitive to the effects. But is this true? Lets find out…

I’m going to cover:

  1. How much caffeine is in your regular brew?

  2. How you might benefit from using caffeine?

  3. What are the risks you need to know about using caffeine?

  4. How To Use Caffeine

  5. Do You Need To Stop Drinking Coffee To Get The Most Performance Benefit?

  6. Take-away Messages

1. How Much Caffeine Is In Coffee (…and other stuff)?

Do you know how much caffeine is in your regular brew? Then take a little look at this:

You’ll notice I put painkillers in the chart – some products contain caffeine to help improve the effects of the painkiller.

2. What Are The Benefits Of Using Caffeine?

There’s been loads of research into the benefits of caffeine (1,2,3,24), but there’s still a lot more to find out (4), such as a greater understanding around anxiety and performance. Pre-event and competitions, we can get a bit nervous or anxious.

Like I used to get a bit anxious before fitness tests when I was in the Army, because I wanted to smash my previous performances (- by the way, I was in the 300 club, thanks!!), and to try to beat as many other people as possible too! Best effort all the way!! And competitive!

Since caffeine can increase the feelings of anxiety (5), having caffeine before your event/competition could further increase your anxiety levels, which could then have a detrimental effect on your performance…defeating the object in the first place!

Research has shown caffeine can be beneficial for:

  • Reducing your perception of fatigue – allowing you to work harder! (5)
    • And the benefit of caffeine seems to be particularly beneficial when you’re fatigued in the mid/later stages of exercise
  • Improving endurance performance (1,6,7), such as running, cycling, cross country skiing (24) and Ironman (9). The 2021 ISSN Position Stand on Caffeine suggests aerobic endurance exercise has the most consistent and greatest level of benefit from caffeine use (24). Caffeine also benefits endurance performance in the heat and at altitude (24), which would be of benefit to military personnel 
  • Improving anaerobic exercise (6,7,8,12), such as resistance exercise – muscular strength and endurance (1,10,11, 24), sprints (12) and cycling time trials (11)
  • Lifting mood and alertness (10,13,15) – hence soldiers use it on Exercises, Tours and Ops for increased attention, vigilance and reaction times, especially when sleep deprived!
  • Cognitive performance (24) – alertness, concentration, complex reaction time, problem-solving and reasoning

3. What Are The Risks Of Taking Caffeine?

Taking more than 6mg per kilogram of body weight increases the risks of side effects such as nausea, anxiety, irritability (21), “jittery”, sleep problems (6,22), increased heart rate (13,20,) and gut issues (7).

Caffeine use is also associated with increased anxiety, so if you’re prone to feeling anxious whether it’s before a competition or not, then you may not want to take caffeine, especially as this could compromise your overall performance.  

Research has shown genetic variation with how caffeine is absorbed, metabolised and used in the body (24, 25), which can then impact the level of benefit, and it’s affect on sleep and anxiety. So it’s wise to test and adjust your caffeine intake to identify your personal benefit and any negative effects (and do it during training rather than saving it for an event/competition where you might get caught out).

Up to 400mg per day isn’t associated with any health risks in healthy adults (22). But having too much caffeine can be harmful (10,13). Death from caffeine appears to be rare (20), but there has been reports in the media over the years.

If you choose to use caffeine supplements, you can help minimise your risks of buying contaminated or fake supplements which could cause you harm, by using Informed Sport certified products.

*Just as an important point to note, having more than 200mg caffeine a day whilst pregnant – about 2 cups of instant coffee, increases risk of miscarriage and low birthweight (19,20).

N.B. If you suffer with IBS (Irritable Bowel Syndrome), then you may need to limit or avoid the amount of caffeine and caffeinated products you use, as it can bring on symptoms in some people. UK clinical guidelines for IBS recommend limiting tea and coffee to a max. of 3 cups per day (26). I’ve had numerous patients and clients who have had issues with caffeine so we’ve had to make some adjustments.  Get in touch if you want help with your IBS symptoms.

4. How To Use Caffeine?

  • Current evidence-based guidelines state 3-6mg per kilogram body weight (total dose) (5,6,9,24)
  • No greater improvement with more than 9mg per kilogram body weight
    • And the risks of side effects increase with over 6mg per kilo body weight (13) and excess can be fatal (24)
  • You can take caffeine in coffee, energy drinks, pre-workout supplements, energy gels, tablets, chewing gum, candy, mouth rinses, aerosols, amongst many other forms of caffeinated products (24)
    • Different sources of caffeine absorb at different rates (24) so you may want to experiment
  • Follow product guidelines for when to take, but usually it’s 30-60 minutes before exercise (6,15,17) although current research suggests this depends on the source of caffeine, for example chewing gum Vs a tablet (24)
  • Can be taken during endurance exercise to give you a boost (11)
    • Note how much caffeine you have so you don’t accidentally overdose (20)

5. Do You Need To Stop Drinking Coffee?

Do you need to stop drinking coffee and stop having other caffeinated products for a certain period of time in order to get the most benefit of caffeine when you do take it?

It seems more research is required because there’s lots of conflicting results and study limitations (24).

But I would say the simple answer is likely no (9,16). Although it is a bit more complex than that.

Response can vary between people and there can be a dose-dependent effect (1,13). So not everyone is going to get the same impact with the same dose. And “more isn’t more” (- see my points above). And there may be a prolonged effect in non-users (15).

There are some studies and reports that have said you need to stop drinking coffee and having other caffeinated products to get the most benefit – to improve your sensitivity to caffeine’s effects.

But some people can get horrible caffeine withdrawal effects which could compromise training in the lead up to taking caffeine so it could end up being counter productive!

Then other sources say you don’t need to refrain from caffeine – caffeine withdrawal doesn’t enhance benefits, or there’s no difference in results between people who regularly consume caffeine, compared to those that don’t (9,15,21).

So my simple answer is no, you don’t need to stop having caffeine to get the most benefit when you do then supplement, but it will be a matter of trial and error and monitoring the effects.

By the way, if you do decide to try caffeine withdrawal to see if you benefit from it’s reintroduction then I’d recommend doing it gradually. Especially if you usually have shed loads of brews every day, because, for example, if you usually have about 6 brews a day and then just stop, then you’re likely to get withdrawal symptoms like headaches and irritability.

6. Take-Away Messages

  1. Beneficial for increasing alertness, mood, endurance and high intensity exercise and reduces perception of effort or pain
  2. If you regularly drink coffee, you don’t need to stop this, to get the most out of using it for your exercise performance (9,16)
  3. Coffee will do! – You don’t have to buy caffeine supplements to get a performance benefit, but different caffeinated products have different benefits, like some absorb quicker from one type of product compared to another and some are easier or more practical to take during exercise, so it’s a matter of weighing up the pros and cons of different products, such as chugging down a brew Vs chewing some gum before/during exercise. And the ideal timing can vary depending on the product
  4. Use 3-6mg per Kilogram of bodyweight (total dose)
  5. Take 30-60mins before exercise (but commonly 60 minutes before exercise although this depends on the product and source of caffeine)
  6. No benefit of taking 9mg or more of caffeine – “more is not more”! And exceeding the dose could be harmful – in the least, you’ll get side effects
  7. Caffeine can compromise your sleep!

The level of potential benefit can vary depending on things like your genetics and the source of the caffeine, so I’d recommend you test and adjust.

P.S. Drinking coffee doesn’t dehydrate you (15,18). More info about fluids and hydration here. Or click on the image below!

Click on the image to read it now

There’s more info about supplements here…or click the picture to read it now.

Click on the image to read it now

I hope you found this useful and interesting. But you need a bespoke plan to get the most benefit! And it’s more beneficial to have your diet dialled in – get the basics right first before dabbling with supplements and performance aids.

It’s crucial to get your food and fluid intake right if you want to control your IBS symptoms, and if you want train harder, go faster and recover quicker from training sessions and competitions. Dietary requirements are highly individualised and there’s no ‘one size fits all’ approach. Working with a Registered Clinical & Sports Dietitian to develop a bespoke plan based on your unique requirements will help to ensure the most appropriate strategy and best results are achieved.

The information, including but not limited to, text, graphics, images and other material contained on this website are for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, examination, diagnosis, or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new treatment or health care regimen, or before making any changes to your existing treatment, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.


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  2. Bach, C. W., & Ransone, J. W. (2018). Caffeine does not increase heat stress during endurance exercise in a hot, humid environment. Medicine and Science in Sports and Exercise, 50(5), S599.
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  12. Salinero, J. J., Lara, B., & Del Coso, J. (2019). Effects of acute ingestion of caffeine on team sports performance: A systematic review and meta-analysis. Research in Sports Medicine, 27(2), 238-256.
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