100, 000 metric tonnes of caffeine are consumed in a year globally. It has been labelled the world's most widely used drug. Caffeine is the gasoline for our hectic lives and busy schedules. It is a staple in our lives, getting us through those tough sleepless days keeping us alert and energetic. It is something a lot of coffee lovers like me look forward to the first thing in the morning. TS Elliot put it best when he said, ‘I have measured out my life with coffee spoons.’  

Caffeine is found in high doses in leaves and seeds of plants, this is toxic to insects. However, in places where it is found in lower does like nectar it can help bees remember and revisit flower. In the human body caffeine is a stimulant for the central nervous system by blocking adenosine. Adenosine is asleep inducing molecule; it is produced when ATP (adenosine triphosphate) is broken down for energy. Neurons are complementary to this molecule and when they bind it causes a slower release of brain signalling molecules and you get sleepy. Caffeine is called an adenosine receptor antagonist. It blocks adenosine from binding with these receptors hindering the adenosine receptor process. Adenosine and Caffeine have similar molecule structures but not similar enough to activate them therefore stimulating you.

Dopamine is a molecule that plays a key role in our pleasure. It is often coined the ‘happy hormone.’ In some neurons adenosine receptors are linked to dopamine receptors. However, when adenosine docks at these receptors' dopamine struggles to. Caffeine does not have the same affect allowing dopamine to be activated.  

There is also evidence to suggest that caffeine can have long- term affects reducing the risk of diseases like Parkinsons Alzheimer's and some Cancers.  

From 1972 – 2004 limits on the concentration of caffeine in an Olympic athlete's blood was placed. This was due to claims that caffeine may give athletes an unfair advantage.  

Not all the effects of caffeine are good. Caffeine can also cause higher blood pressure and heart rate, cause diarrhea and contribute to insomnia or anxiety.  

Regular coffee drinkers will find that their brain may adapt to caffeine, if our adenosine receptors are clogged our bodies form more adenosine receptors. Therefore, if caffeine is suddenly stopped it can cause headaches, drowsiness, and a drop in mood. Over a couple of days our bodies will readjust bringing our energy and focus back up with it.