Coffee Makes Me Tired: 4 Scientific Explanations In 2024

It’s a curious phenomenon: “Coffee Makes Me Tired.” Sounds paradoxical, right? After all, coffee is the go-to drink for a quick energy boost. Yet, for some, it does the exact opposite. This isn’t just a random occurrence; there’s science behind it.

In this post, we’ll dive into the intriguing reasons why coffee, despite its popularity as an energy booster, can sometimes leave you feeling more ready for a nap than a productive day. That’s because coffee has a complex relationship with our bodies, sometimes leading to fatigue rather than alertness.

And here’s why coffee makes you tired in short:

  1. Adenosine Rebound & Caffeine Crash
  2. Dehydration and Energy Levels
  3. Impact on Blood Sugar
  4. Psychological and Lifestyle Considerations

And here is what you can do against coffee making you tired:

4 Reasons Why Coffee Makes You Tired

1. Adenosine Rebound & Caffeine Crash


Feeling tired after drinking coffee can be quite puzzling, considering that coffee is renowned for its stimulating effects. This phenomenon, often referred to as “adenosine rebound,” has everything to do with the chemical adenosine and its role in regulating our sleep-wake cycle, as well as caffeine’s temporary blocking of adenosine receptors.

Role of Adenosine in Sleep-Wake Cycle

Adenosine is a central nervous system neurotransmitter that plays a key role in our sleep-wake cycle. Throughout the day, our body naturally produces adenosine, a process linked to neural activities during wakefulness. The levels of adenosine gradually increase, eventually making us feel drowsy as it builds up; this is our body’s way of signaling that it’s time to rest.

Caffeine’s Blocking of Adenosine Receptors and the Subsequent Rebound Effect

When we drink coffee, caffeine acts as an adenosine receptor antagonist. It competes with adenosine and temporarily prevents it from binding to its receptors in our brain. This blockage makes us feel more alert as it stops the natural accumulation of adenosine from telling our brain that we’re tired.

However, this is a temporary effect; as the caffeine eventually wears off, what follows is a caffeine crash. When this happens, there is a sudden increase in adenosine receptor activity, leading to a rebound effect of sleepiness as the accumulated adenosine can now bind to its receptors. This is why you might feel more tired after the initial alertness provided by coffee wears off.

✒️ Summary

Drinking coffee blocks adenosine, a chemical that makes you sleepy. When the coffee wears off, adenosine builds up quickly, making you feel tired.

2. Dehydration and Energy Levels


Caffeine as a diuretic and its impact on hydration

Caffeine, a natural diuretic found in coffee, increases urine production. This can lead to a net loss of fluids if we don’t compensate by drinking water. For example, after our morning cup, we might make frequent trips to the restroom, which can gradually deplete our body’s water levels. If we experience increased urination from coffee and don’t replenish our fluids, this might initiate a dehydration cycle that contributes to fatigue.

The link between dehydration and fatigue

Fatigue often accompanies dehydration. It’s a clear signal from my body that it’s running low on water, crucial for energy production and efficient bodily functions. Even mild dehydration can impede cognitive functions, like memory, and heighten feelings of anxiety. Staying hydrated is important to maintain my energy levels throughout the day, especially when I consume diuretics like coffee.

However, it is important to mention that moderate coffee consumption may not significantly impact dehydration.

✒️ Summary

Caffeine in coffee increases urination, which can lead to dehydration and fatigue if not balanced with water intake. However, moderate coffee drinking usually doesn’t cause significant dehydration.

3. Impact on Blood Sugar


Caffeine can influence our blood sugar levels and it can have effects on our sleep quality. Understanding these interactions is crucial for anyone feeling tired after coffee consumption.

Caffeine’s Effects on Blood Sugar Levels and Insulin Sensitivity

Caffeine has complex effects on blood sugar and insulin sensitivity. While our body’s response to caffeine is personal, it’s common for the substance to cause short-term spikes in blood sugar levels. This happens because caffeine may stimulate the release of adrenaline, which can inhibit insulin activity. In turn, reduced insulin sensitivity means sugar remains in my bloodstream longer instead of being used for energy, which could leave us feeling tired once the caffeine boost wears off.

This ‘sugar crash’ phenomenon is more severe if coffee is consumed on an empty stomach, leading to an intensified energy crash. To mitigate this, pairing a coffee with a meal that includes protein and healthy fats can help stabilize blood sugar levels, offsetting the adverse effects of both caffeine and sugar on energy and tiredness.

✒️ Summary

Caffeine can cause short-term increases in blood sugar levels, potentially leading to reduced insulin sensitivity and energy crashes. To stabilize blood sugar, it’s beneficial to consume coffee with a meal rich in protein and healthy fats.

4. Psychological and Lifestyle Considerations


Stress and Mental Health Impacts (e.g., Anxiety)

When under a lot of stress or dealing with anxiety, coffee doesn’t quite work as it should for some people. Instead of invigorating, it can make us feel more run down. Anxiety can play a big role in this, as it usually leads to increased production of stress hormones like cortisol, which can be further exacerbated by caffeine.

Under a hefty load of stress, our body produces more cortisol, which is known for its affiliation with stress responses. Coffee can boost cortisol levels, which if already high due to ongoing stress, could lead to an increase in feeling exhausted rather than energized.

Dietary Habits and Overall Health

Dietary choices also significantly shape how coffee affects us. If consumed on an empty stomach or with a diet high in refined sugars, coffee might cause a quick spike in blood sugar followed by a crash, resulting in tiredness. Moreover, maintaining a balanced diet and staying hydrated are key to optimizing the benefits of caffeine and minimizing the drawbacks.

✒️ Summary

Coffee can increase stress hormone cortisol levels, which may worsen feelings of exhaustion, especially in already stressed individuals. Additionally, consuming coffee with a poor diet, particularly on an empty stomach, can lead to blood sugar spikes and crashes, contributing to tiredness.

What You Should Do To Fix Coffee Making You Tired

If you’ve noticed coffee makes you tired, I have some tips that may help you tackle this issue. By making a few adjustments, you can enjoy your coffee without the unwanted fatigue.

  • Adjust Your Coffee Intake Timing
    Consider drinking coffee at times when your energy is naturally lower, such as mid-morning or early afternoon. Try not to drink coffee late in the evening. This might disrupt your sleep-awake-cycle.
  • Stay Hydrated
    Due to coffee’s diuretic effect, it’s crucial to drink plenty of water. Dehydration can make you feel tired, so balance each cup of coffee with a glass of water to stay hydrated.
  • Check Your Coffee’s Sugar Content
    Reducing or eliminating added sugars in your coffee can prevent the energy crash that often follows a spike in blood sugar. Opt for less sugar or try using natural sweeteners. Pair your coffee with a meal to prevent a sugar crash.
  • Avoid Coffee When You’re Stressed
    Under stress, our body produces more cortisol. Coffee can boost cortisol levels, which could lead to an increase in feeling exhausted rather than energized.
  • Try Decaffeinated Coffee
    If caffeine might be the reason why you feel tired when drinking coffee, you should give decaffeinated coffee a try. That way you can still enjoy your coffee whenever you want.

💡 Other Effects Coffee Might Have

Coffee has many benefits. But every once in a while there might be disadvantages. Here is a quick overview of other side effects of coffee:

FAQ – Coffee Makes Me Tired


Why does coffee make me tired immediately?

You may have experienced times when coffee made you feel tired almost right after drinking it. It might seem strange since coffee is a stimulant, but it’s actually due to its diuretic effect, which can lead to mild dehydration, often manifesting as tiredness.

Does coffee make ADHD people sleepy?

For some individuals with ADHD, coffee or other sources of caffeine can indeed make them feel more relaxed or sleepy. This is thought to stem from how caffeine interacts with the brain’s chemistry differently for those with ADHD.

Can caffeine have the opposite effect?

Yes, caffeine can have the opposite effect of what many expect. While it usually increases alertness, for some people, it can lead to increased tiredness after the initial effects wear off. This can be due to a number of factors including tolerance and the way caffeine affects sleep-wake cycles.

How do you stop coffee from making you tired?

To prevent coffee from making you tired, focus on staying hydrated, limit your caffeine intake, and do not drink coffee close to bedtime. Ensuring that you get adequate sleep and physical activity are important too, as they are primary ways to combat fatigue.


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Wadim Urbanowitsch

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