Caffeine disrupts your 24-hour sleep-wake cycle by changing adenosine activity. Adenosine could be described as the “tiredness chemical”: towards the end of the day it binds to receptors all over the brain and prevents neurons from firing, making us feel groggy and tired. Caffeine disrupts this natural regulation of tiredness. Next time you are sipping a cappuccino, picture the caffeine molecules racing against the ”tiredness chemical” in your brain, competing for a spot on your adenosine receptors. When adenosine wins the race, it makes us sleepy. When caffeine wins, it takes up the place of adenosine so that it can’t make us sleepy.
The more coffee you drink, the harder it is to stop. When you start having coffee frequently, the brain compensates for higher levels of caffeine by releasing more of the “tiredness chemical” than it did before. This makes us feel extreme fatigue without coffee, so that eventually you need that first coffee in the morning to wake you up for the day. This is the scary progression from drinking coffee occasionally because you like the taste, to needing it to be able to function!
The more coffee you drink, the harder it is to stop
This article is not to scare you away from drinking coffee – in fact, I have been sat in a café with a cappuccino as I’ve written it. Coffee can enhance memory processes by increasing the availability of acetylcholine in the hippocampus, so it is unsurprising that so many students become reliant on it during exam season. However, coffee’s hidden addictive properties are something to be aware of, because drinking coffee frequently can lead to delayed sleep onset, poorer sleep quality and even symptoms of insomnia!