A Balanced View on Caffeine

There is increasing research showing that caffeine improves various aspects of brain function. From memory, mood, vigilance, energy levels to reaction times caffeine can be of benefit. It does this by blocking the function of a neurotransmitter called adenosine. Caffeine stimulates and excites. This can be really useful at certain times but then again maybe not ideal when we are trying to relax and sleep, we really do need the calming effect of adenosine to come into play.

So, if some caffeine can be good for you a question we are often asked is how much? As with most things everyone is different but as a general guide, we suggest you try and avoid more than 300mg of caffeine per day. What does 300mg look like, well the table below will give you an idea.


Drink Caffeine per litre (mg)
Filter Coffee 550 – 850
Percolated Coffee 380 – 650
Espresso  1690 – 2254
Black Tea 282
Green Tea 172
Red Bull 320
Coca-cola 96

It is not just the quantity of caffeine that is taken on board that can be a challenge it is also when it is consumed. Caffeine has a chemical half life of around 5 hours. That means if I picked up one of those extra-large coffees you can get at various locations along the high street at around 5.00 p.m. I would be taking on board around 400mg of caffeine and 5 hours later at 10.00 p.m. just when I am starting to think about going to bed, I’d still have 200mg of this stimulate in my system. Timing is important and I try to avoid strongly caffeinated drinks after 2.00 p.m. so that when I do try and go to sleep, I give my adenosine the best chance to work!

The last point to make about caffeine is that it is addictive. The more you drink the more you will want. This may seem alarming, however you can release this particular addiction very quickly. It could be worth trying to avoid caffeine totally for one week every quarter – this should reset your craving for caffeine!