For many of us, the morning wouldn’t be complete without that first cup of coffee to shake off the cobwebs and get the day rolling. We love it for the flavour, the culture, and of course, the buzz that we get when we get a caffeine hit.

Caffeine is such a commonly taken drug that three in four Australians have at least one cup a day. But given that 75 percent of us are guzzling the stuff on the regular, do we actually know how caffeine works?

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The way caffeine works on your brain is that it inhibits a natural neurotransmitter called adenosine (a calming hormone), which naturally builds up throughout the day, making you feel tired as the day progresses. 

When you consume caffeine, it’s not so much that you’re getting a boost in energy, rather you’re getting a temporary reprieve from these naturally occurring sleepy hormones.

The reason for this phenomenon is that caffeine blocks specific receptors in the brain that mediate critical functions like sleep, arousal, cognition, memory, and learning. When these receptors are operating as usual, it slows brain activity, causing sleepiness or drowsiness.

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When we drink a cup of coffee, the caffeine is absorbed through our digestive system and into the bloodstream, where it crosses into our brains. The receptors in our brains that would normally be absorbing adenosine (the sleepy stuff) become blocked by the caffeine and neurotransmitters, that is our chemical messengers, take a little break.

Speaking of which, might be time for a coffee break.

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