Caffeine Fatigue: 7 reasons Why Your Cup Of Coffee Makes You Feel Tired

In this guide, we explain the concept of caffeine fatigue and why coffee can make you feel tired.

Sleep is a chronic problem in this country and it might be due to caffeine fatigue. Too many people struggle to fall asleep at night while others might have issues staying asleep once they crawl into bed.

If you feel tired when you wake up in the morning, you are not alone. There are lots of people who struggle to keep their eyes open as they struggle through the morning routine.  

This is one of the biggest reasons why people drink coffee to start their day. You might feel better once you drink that cup of coffee; however, the real reason why coffee makes you feel more alert is the caffeine.

On the other hand, you might also feel tired in the afternoon. How does this work?

Why does drinking coffee help in the morning but make my afternoons feel groggy? There are a few key points that you should keep in mind.

How Does Caffeine Reduce Fatigue?

Caffeine is closely tied to energy because of the impacts it has on your neuromuscular system. This system plays an important role in letting your body know when it feels tired and when it has energy.

In this manner, caffeine can partially counteract the negative effects associated with neuromuscular fatigue by targeting the motor cortex in your brain. 

Basically, caffeine makes it feel like it takes less effort to accomplish different tasks throughout the day. This is how caffeine can reduce fatigue.

Does Caffeine Affect Your Energy Levels?

By drinking coffee, caffeine stimulates your body’s nervous system. The nervous system is responsible for controlling your body’s vital signs such as heart rate, blood pressure, and respiration rate.

When you drink caffeine, you are raising your body’s heart rate and blood pressure. This will help you increase your body’s energy levels and improve your mood.

When you feel happy, you naturally have more energy. This is what people usually call a “caffeine high.” Caffeine acts quickly. You might even notice the effects of caffeine within minutes. 

Does Caffeine Drain Your Energy?

If you are thinking “coffee makes me sleepy,” you are not alone. This is called caffeine fatigue. Given that we just discussed how caffeine helps you feel more awake and alert, how can it also drain your energy

If you are asking, “why does caffeine make me tired,” there are several reasons why this might be happening. These include:

1. Coffee Blocks Adenosine

The first reason why caffeine can lead to fatigue is that this blocks the effect of a molecule called adenosine. When you drink coffee, your body absorbs caffeine through the stomach and small intestine. Then, caffeine travels throughout your bloodstream to various parts of your body, including the brain.

Once caffeine reaches the brain, it blocks adenosine receptors. Adenosine is responsible for making you feel sleepy. Therefore, when caffeine is in your system, adenosine cannot bind to its receptors. As a result, you feel more awake. Once the caffeine leaves your body, you are hit with a flood of adenosine. This makes you feel tired.

2. Coffee Is a Diuretic

Coffee is also a diuretic. Basically, when you drink coffee, you go to the bathroom more often. You might have noticed this yourself. If you only drink one cup in the morning, you might not notice anything; however, if you drink four cups of coffee, you might end up running to the restroom.

When you go to the bathroom more often, you encounter dehydration. Some of the symptoms of dehydration include a dry mouth and a lack of sweat. Dehydration can drop your blood pressure, making you feel tired.

3. There Is Sweetener in the Coffee

If you use sweetener in your coffee, you might end up feeling more tired in the afternoon. You probably drink coffee in the morning and you probably add cream and sugar. Sugar contains sucrose, which is table sugar. The cream contains lactose, which is another sugar.

Sugar gives you energy; however, when the sugar wears off, your blood glucose levels start to drop. This is a sugar crash, which makes you feel tired. Think about eating protein with lunch to balance out your blood sugar levels.

4. Chronic Coffee Use Leads to Caffeine Tolerance

Another potential reason why you might be noticing caffeine fatigue is that you are a chronic coffee drinker and you have developed something known as tolerance. Over time, your body gets used to having caffeine in its system and doesn’t respond as readily to it. Therefore, you need to drink more to achieve the same results.

As you drink more coffee to feel awake in the morning, the side effects of caffeine use become exacerbated. This causes you to feel more tired in the afternoon. While it might be hard, the answer could be to wean from caffeine.

5. Caffeine Leads to Stress

There are lots of reasons why you might feel tired and one of the most common culprits is stress. Financial stress, work stress, and family stress can drain your energy levels, making you feel tired.

Studies have shown that caffeine can increase levels of stress hormones such as cortisol and adrenaline. This means that you might feel more stressed after drinking your morning cup of coffee. Your body tries to avoid stress by making you feel sleepy.

6. Caffeine Withdrawal Is Developing

If you consume caffeine on a regular basis and suddenly go a day or two without it, you might develop something known as caffeine withdrawal. Withdrawal develops when your body gets used to having something in its system only to have it taken away abruptly. 

Caffeine withdrawal symptoms can be serious. Some of the most common symptoms include headaches, nausea, vomiting, irritability, and difficulty concentrating. One of the biggest symptoms of caffeine withdrawal is sleepiness. Usually, caffeine withdrawal sets in between 12 and 24 hours after your last cup of coffee.

Caffeine withdrawal can directly lead to fatigue. If you want to avoid this syndrome, you need to wean off of caffeine gradually. This will help you avoid feeling tired.

7. You Consume Caffeine in the Afternoon

Finally, one of the most common reasons why caffeine makes you feel tired is that you drink it in the afternoon. You know the story. You feel tired in the afternoon because of all of the reasons listed above. Then, you decide to drink caffeine in the afternoon to wake up.

All of a sudden, you are wired again so you can’t sleep. Therefore, when you get up in the morning you already feel tired. Your cup of coffee yesterday afternoon is making you feel tired this morning. To avoid this problem, avoid caffeine in the afternoon. You will sleep better at night.

Caffeine Consumption in Moderation

If you are wondering, “why does coffee make me sleepy,” the answer has to do with caffeine fatigue. These are a few of the many reasons why caffeine makes you feel tired. While there is nothing wrong with having a small cup of coffee in the morning when you wake up, it is important to have a limit on your caffeine consumption. 

Drinking too much caffeine can lead to dehydration, stress, and caffeine withdrawal down the road. All of this can actually make you feel tired. The next time you use your coffee grinder, watch your caffeine consumption closely.


  • David R

    Job experience includes extensive work as a teaching assistant, tutor, and guest lecturer and extensive employment in the healthcare field. Have published multiple research papers and numerous poster presentations on various healthcare research topics. Find David on WriterAccess.