What is caffeine?
Caffeine is a naturally occurring stimulant that is available in several different forms; we can find it in food (chocolate), drinks (tea, coffee, energy drinks), as well as in tablet and powder form. Whilst caffeine is the main active ingredient in coffee, it contains other compounds which can make it difficult to identify the direct effects of caffeine as opposed to other ingredients.
There have been many claims that caffeine is not good for us but the truth is that in moderation, it can have many health and performance benefits.
The European Food Safety Authority (EFSA) suggests that around 400mg of caffeine per day can be enjoyed as part of a healthy balanced diet. A normal cup of coffee contains 75-100mg caffeine which equates to 5 cups a day, tea and cocoa are typically lower in caffeine.
Pregnant and breastfeeding women are advised to lower their caffeine intake; no more than 200mg per day is recommended. Decaffeinated versions are readily available.
The Coffee and Health organisation have provided the following guidance on caffeine levels in many popular foods and drink:
Caffeine’s diuretic effects
It is true that caffeine is a mild diuretic but, contrary to popular belief, consuming it in tea or coffee doesn’t dehydrate you. Such drinks also provide ample amounts of fluid which negate the dehydrating effects. Unless, of course, you are drinking copious amounts of espresso every day – in that case, you may wish to refrain or at least attempt to cut back.
Tolerance to caffeine
As caffeine is a ‘drug’, we can become tolerant which, in turn, dampens its effect. It is also very possible to become dependent on it. One way of mitigating this would be to have a caffeine free day once a week.
How caffeine reacts in the body
We do not get an instant ‘hit’ from caffeine, it takes our bodies 45 minutes to metabolise it when it then becomes available throughout the blood and most parts of the body, including our brain. As it starts entering your brain, it starts opposing adenosine, a ’sleepiness’ molecule. Caffeine tends to peak in the blood after about 2 hours which is when we feel the most benefits. It has a half life of 4-6 hours which means that if you have 200mg at 8am, you will still have 100mg in your system at 12pm. It is therefore not advisable to consume too close to bedtime.
Caffeine as a performance supplement
Caffeine is a highly recommended performance supplement for a number of reasons. First of all, it spares muscle glycogen (Greer et al, 2001). This helps to increase energy levels and enhance endurance meaning you can work out for longer. It also means that you burn fat instead of glycogen but this does not equals fat loss unless you are in a calorie deficit.
Caffeine also increases alertness and improves decision making, particularly when sleep deprived (Kamimori et al, 2015), and can also increase strength during exercise which means enables you to work out harder (Placket, 2001).
It reduces reaction time meaning that you perform more effectively and also improves muscular endurance so that you tire less quickly.
Another key benefit for athletes is that it reduces RPE; a scale used to assess how difficult someone perceives exercise to be. This is an important factor in determining exercise intensity; the less exerted you feel, the better you will perform.
Caffeine can therefore be a very useful supplement for endurance and strength athletes alike.
How to supplement
To get the most benefit during an exercise session, it is best to consume caffeine 60 minutes prior to ensure it has been metabolised effectively. Effects are unlikely to be felt if consumed immediately before.
Tea and coffee do not have the same effects as a caffeine supplement which is a worthwhile consideration if you want to increase performance and strength. 2-6mg per kg of body weight is usually recommended. To get the most benefit, it is could also be worth decreasing your daily consumption so that you are not dampening the effects around training.
In addition, there has been research to suggest that caffeine can help to reduce appetite although the data is conflicting with some believing that it has a placebo effect. For example, if you wake up hungry but opt for a coffee, it could psychologically lead to you skipping breakfast.
There is also some evidence highlighting that it can slightly increase metabolism (Astrup et al, 1990) which can have an impact on energy balance.
Caffeine is a natural stimulant that can be enjoyed in moderation as part of a healthy, active lifestyle. It can help to improve performance, reduce the effects of fatigue and even acutely assist with weight loss.
This was brought to you by Rebecca Flannery, Evidence Based Nutritionist at Transformational Nutrition.