Why Does Coffee Help People Stay Awake?

It’s a common and unfortunate paradox of life that many people experience: when one is trying really hard to fall asleep, your eyes just don’t seem to get heavy, but when one is desperately trying to stay awake…. well, you get it.

Many people use different tricks and techniques to keep their eyeballs from losing focus and drifting off to sleep. One such technique to stay awake is to drink coffee (or tea, for some). Drinking hot beverages is very common for students while cramming in their final studying on the eve of exams. Somehow, drinking coffee or tea (caffeine-rich beverages) helps you stay awake.

Have you ever wondered why?

Steaming Coffee


Caffeine and the Brain

First, let’s see why we get drowsy in the first place.

Throughout the course of a day, we (most of us, at least) find ourselves busy doing different kinds of activities. Some of these are more physical in nature, whereas others are mentally grueling. Whether physical or mental, the brain has to ensure that you’re up and running, and thus has the responsibility for coordinating the functions and actions of all the body organs.

While doing this, the neurons in the brain produce very small quantities of adenosine. Because the production of adenosine is very gradual, a person feels drowsy over a long period of time. It’s not as though you suddenly feel drowsy;  drowsiness is something that creeps up on you very slowly – sneakily drawing you into slumber.

adenosine and caffeine

Structures of caffeine and adenosine

Functions of Adenosine

Why does adenosine result in gradual drowsiness throughout the body?

Adenosine molecules become bound to the neural receptors of the brain, which are in charge of receiving signals from all over the body and staying sharp. However, when adenosine molecules bind to these receptors, their activities slow down and eventually… zzzzz…. you’re already drowsy!

Caffeine and Adenosine

Caffeine enters this picture when you drink coffee, tea, or some other caffeine-fueled beverage. Caffeine is a very smart substance, as it binds to the adenosine receptors in the brain, essentially blocking the molecules that cause slowing down brain activity.

This is very similar to the idea of ‘two negatives make a positive.’ Adenosine slows the activities of the brain, but caffeine binds to adenosine molecules and slows down their activity. This is why the activities of brain go unchecked and you are able to fend off feelings of drowsiness.

Coffee Beans Bread

Credits:Aleksandrs Samuilovs/Shutterstock

Not only does caffeine keeps adenosine in check, but it also causes the production of more adrenaline and increases the heart rate, effectively keeping you all pumped up.

Coffee is truly a great thing to drink if you’re feeling your eyelids start to droop. However, it would be a much better idea to properly prepare for exams and not depend on caffeine to get yourself an A!


  1. About Caffeine – Villanova University
  2. How Stuff Works
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About the Author

Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spends a lot of time watching movies, and an awful lot more time discussing them. He likes Harry Potter and the Avengers, and obsesses over how thoroughly Science dictates every aspect of life… in this universe, at least.

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