Why Does Coffee Make Me Tired?

Hitting the midday slump, have you ever tossed back a fresh cup of drip coffee only to hear yourself yawn just a few minutes later? You’re not alone my friend, because I’ve experienced this heartbreak as well.

Though it’s known round the world as the go-to stimulant, why does coffee make me tired sometimes? Like most paradoxes, there is no simple response to this question.


One of the first things you should understand about coffee is that it affects everyone differently.

For some people, they might as well be drinking a cup of hot water for all the stimulation (or lack thereof) that they feel.

Caffeine, the prized ingredient in coffee, works by blocking adenosine receptors in the brain, which are commonly associated with sensations of fatigue. This means that caffeine essentially tricks your mind to keep going, even when it should be taking for a rest.

Though scientists have yet to pinpoint exactly why caffeine has less of an effect on some individuals, they at least know where to look: in our genes.

A study conducted on lab rats found that one or more recessive genes limit caffeine susceptibility.

Unfortunately, this experiment could not ethically be carried out on humans, what with cloning still outlawed and all, but it does give us some insight into how our own bodies are affected by caffeine. Whereas most people will feel the coffee kick, some will be as ignorant of the effects as Donald Trump is to reality.

Caffeine Dependency

However, genetics aren’t the only reason you may feel tired after drinking coffee.

Your coffee yawns may be a result of an intense match of king of the hill going on in your body.

In case you were unsure about this, stimulating your mind into alertness with a drug when it should be at rest is not a natural bodily function. Though its effects are desirable, using caffeine creates a momentary imbalance in your brain.

If you take in a high dosage at regular intervals daily, you are never giving your mind the opportunity to have a natural rest.

So what does your brain do? Exactly what you’d expect it to: fight back!

The more you block your adenosine receptors, the more your brain will create in an attempt to compensate.

If you keep upping your caffeine intake, this back-and-forth rivalry will continue until you eventually develop a partial immunity or become dependent on caffeine, or both.

Your brain will have produced so many adenosine receptors that you’d have to maintain your ridiculously high caffeine intake just to function on a normal level.

Caffeine Conditioning

Apart from the caffeine induced chemical reactions going on in your brain, there may be another, more behavioral, reason for your fatigue.

There is a fun little psychological concept called classical conditioning, which is basically just a method for programming specific behaviors on cue. This process isn’t the easiest thing to pull off, yet it can happen, and you can even do it to yourself.

Many people use self conditioning to change a behavior they don’t want, like smoking or unhealthy eating, but it can even happen unconsciously.

To give an example, if you continuously eat M&Ms whenever you’re happy, randomly eating an M&M could make you feel happier. Just about any emotional or behavioral reaction can be conditioned with just about any stimulus, including coffee.

 If you typically drink your coffee while relaxing, like breaking from work or lounging on the cafe terrasse, then you could condition your mind to feel relaxed whenever you drink coffee.

Sweet Dreams…

Another factor to consider is whether you drink your java with large amounts of sugar or not.


Because apart from its deliciously desirable sweetening effect (and that caffeine-like sugar rush), sugar also brings along with it a not-so-sweet counter-effect: the sugar crash.

If you’re used to hopping up on a combo of java AND sugar, there’s a good chance that — caffeine and coffee aside — you’re just plain suffering from a sugar overdose!

While caffeine literally tricks your brain into thinking you’re not tired, sugar just plain gets used up by your body, and once that happens ...you crash.

If you drink especially sweet coffee, keep this one in mind when you’re looking for a pick-me-up and try to dial back the sugar!

The Caffeination Dehydration Cycle

Ah, crap, the topic that just keeps on giving. No matter how meaningful a conversation is, it always ends up spiraling down to a discussion about poop sooner or later. ...and the same goes for coffee tiredness.

The truth is, coffee and crap often go hand in hand when it comes to feeling tired. This is usually because of a vicious problem that Driftaway Coffee expertly outlined, and which we will here call the “caffeination dehydration cycle.”

The caffeination dehydration cycle begins when you’re tired. 

You reach for a cuppa hoping to solve the problem. However, while the caffeine can be a pleasant tool, there’s another thing that coffee does to your body besides wake it up ...it makes you dehydrated.

This happens because coffee is a diuretic, which means it causes you to pee not long after consuming it. This, of course, can dehydrate you.

When you lose too much water, your blood begins to thicken, which delivers less oxygen to your body, leading to a feeling of lethargy.

And how do we address lethargy? Perhaps we drink some water, but chances are — especially if we’re tired — we’re just going to reach for some more of that damning brew, perpetuating the caffeination dehydration cycle in the process.

The lesson here: make sure you’re drinking water along with your coffee when you’re feeling tired!

So now you know...

Although there is no simple answer to the question, “Why does coffee make me tired?” there are a few things you can do to solve this problem:

  • Only drink coffee when you plan to be active.

  • Cut back when it stops working.

  • Reduce the amount of sugar you take with your java (if you add sugar in the first place!)

  • Make sure to stay hydrated!

Let me know in the comments below if you have any questions!


Alex is the Founder and Editor of Homegrounds.co. He is passionate about brewing amazing coffee at home, and teaching others to do the same.

Click Here to Leave a Comment Below 5 comments
Rutger - June 15, 2017

For a small number of people caffeine triggers insulin, which lowers the blood sugar and makes them sleepy to the point they almost crash. This is quite common among people who suffers from migraine with aura. Getting sleepy by caffeine is also quite common among people with ADHD/ADD diagnosis.

John - May 5, 2018

Political slant within article is childish. Have you always been a petulant child?

    Alex - May 6, 2018

    I guess my humour isn’t for everyone, right John?

Rachel - June 1, 2018

Thank you for the short and sweet answer! I love drinking coffee for the taste but sometimes it makes me feel so tired.
Another WEIRD thing is TYPES of coffee! For example, Starbucks coffee I get energetic but if I drink dunkin donuts coffee it’s like someone literally drugged me with five sleeping pills.

BOTH are the same drinks, a small black no sugar iced coffee… that’s it! Yet they have different effects on me. Now I’m interested on the type of coffee, type of roast/blend effects on ones body. How is it the same drink, but different coffee affects, me at such different extremes? I would love to know!

    Don - September 27, 2018

    Rachel exactly! I literally googled Dunkin Donuts coffee makes me tired and found your comment. I would love to know why certain coffees have different effects too.


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