7 Reasons Why Coffee Could Make You Tired

Cup of coffee in bed with an open book and glasses

If you drink a lot of coffee, then you’ve probably experienced a caffeine crash. One minute, you’re riding the wave of your afternoon energy boost, and the next you’re a zombie in desperate need of a nap. What happened?

Although it’s strange to think that caffeine can actually make you tired, it’s pretty common. Here are some of the main reasons that coffee might be making you tired.

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How Does Coffee Work?

Coffee is a popular part of many people’s morning routines, and it’s no wonder why. One cup of black coffee contains a whopping 96 milligrams of caffeine.

Caffeine is well-known for its energy-boosting abilities, which are thanks to the way that caffeine molecules closely resemble adenosine molecules. This affects your central nervous system to create feelings of alertness and energy. 

Normally, adenosine is supposed to accumulate throughout the day due to physical and mental exertion. When adenosine levels build up in your brain over the course of your day, you should start to feel more tired. This is a part of your body’s natural rhythm and plays a huge part in your sleep-wake cycle.

However, since caffeine looks so much like adenosine, it can bind to your adenosine receptors. This means that caffeine blocks adenosine from helping you get tired.

Not only does this prevent your daily buildup of adenosine from inducing tiredness throughout the day, but it also increases your energy levels. This type of activity is what makes caffeine a stimulant.

When you drink coffee or any other caffeinated beverage, the caffeine is absorbed through your small intestine. Within an hour of your first cup of coffee, the caffeine is fully absorbed into your bloodstream.

Once absorbed, caffeine slowly leaves your system over the course of the day. The exact time frame depends on how fast your body metabolizes caffeine, but most of the time caffeine is out of your system ten hours after your cup of joe.

Reasons Coffee Could Make You Tired

If caffeine is supposed to give you energy, how could it have the opposite effect? Here are some of the main reasons why coffee can make you tired.

Caffeine Can Increase Stress

While it can be relaxing to sit in your favorite chair with your morning cup of coffee, it’s a different story once that caffeine hits your system. 

Caffeine can put you on high alert, thanks to an increase in adrenaline. If you continue to drink coffee throughout the day, the constant adrenaline rush can leave you feeling agitated and edgy. Being on high alert constantly requires a lot of energy, so you’re even more likely to experience a major energy crash once the caffeine finally wears off.

Caffeine can also increase your body’s natural production of cortisol, also known as the “stress hormone.” An increase in cortisol and adrenaline can negatively affect your blood pressure and your heart rate, which can also result in a huge energy crash once you’re able to calm back down.

The good news is that you have to have a pretty high caffeine intake to see these effects. A soothing cup of caffeinated tea or a single cup of coffee is unlikely to result in elevated stress levels. 

If you want to avoid the stress, we recommend a nice cup of earl grey. Not only does earl grey contain less caffeine than coffee, but it also has several other health benefits. 

(Plus, the caffeine in tea is absorbed differently by your body than the caffeine in coffee for a more sustainable energy boost without the jitters or crash.)

You Might Have a High Tolerance

If you drink a lot of coffee, you might feel like it takes two or three cups of coffee before the energy-boosting effects of caffeine kick in. This is because you can actually develop a tolerance to caffeine.

If you drink a lot of coffee drinks, your body eventually gets used to running with that much caffeine in its system. In other words, it depends on high amounts of caffeine to function.

When this happens, even one cup of coffee isn’t enough to wake you up. So, while your regular caffeine consumption is meant to keep you awake, the caffeine tolerance you can build up does quite the opposite.

Your Coffee Has Sugar

Many people sweeten their morning cup of joe, and we get it – coffee can be quite bitter, and that French vanilla sweetener is so delicious. However, this dose of sweetness may be contributing to your energy slump.

Drinking large amounts of sugar raises your glucose level. While this can lead to a high-energy sugar rush, you’ll also get the dreaded sugar crash. 

As your blood sugar levels continue to rise, you might notice fatigue and drowsiness replacing your short spurt of energy. This is especially noticeable in sugary espresso drinks. Despite the caffeine content of your morning pick-me-up, chances are you’ll end up more tired than before.

Adenosine Sensitivity

We mentioned earlier that caffeine blocks adenosine receptors. While this is part of what makes caffeine work, it can also result in more tiredness.

Drinking caffeine too late can lead to sleep deprivation, which can actually cause your body to release more adenosine than normal in an attempt to regain sleep. Think of it as your brain’s version of a force-quit.

Not only does your brain release more adenosine, but it also increases your sensitivity to the chemical. The combined effect is a double whammy that can leave you ultra-tired way before bedtime.

You’re Dehydrated

If you feel like your trips to the restroom increase after a cup of coffee, you aren’t wrong! Coffee is a diuretic, which means it increases urination and can ultimately lead to dehydration.

Being slightly dehydrated can make you tired, and can also increase feelings of stress, impair memory, and impact cognitive performance. Basically, your daily coffee intake might not make you as productive as you feel.

If you drink coffee later in the afternoon, you may find that these frequent trips to the restroom can even impact your sleep. If you’re waking up multiple times in the night to use the restroom, then you might not get enough sleep. This can result in more drowsiness than usual in the morning, and it may make you more tired throughout the day.

Caffeine Has Affected Your Sleep

Many coffee lovers drink coffee throughout the day to stay awake. While the energy-boosting effects of coffee and other caffeinated drinks might help in the short term, they can result in long-term tiredness.

Caffeine prevents you from getting tired until it’s out of your system, which can take up to ten hours depending on your metabolism. We love an afternoon cup of coffee, but drinking coffee past ten in the morning can prevent you from getting tired at the right time.

This often results in sleeplessness, which can then result in sleep deprivation. With sleep deprivation also comes reduced response times, alertness, and ability to concentrate.

When you are seriously lacking sleep, your first reaction may be to reach for the coffee to get yourself through the day. However, this can exacerbate the issue and create a negative cycle.

Lifestyle Factors 

Your metabolism has a huge impact on how caffeine affects your system. The faster your body metabolizes caffeine, the quicker it’s out of your system and the sooner the feelings of tiredness come back.

Your metabolism is largely based on genetics, although there are some outside factors that can influence how your body metabolizes caffeine. For instance, regular smoking can increase your caffeine metabolism, which means you’ll get tired faster than normal. The good news is that studies have shown that once you stop smoking, your body quickly returns to its normal metabolism.

On the other hand, pregnancy and oral contraceptives can increase your caffeine metabolism, which means that it will take longer for caffeine to leave your system. This means that it’s even more important to avoid coffee in the afternoon or evening.

How to Avoid the Caffeine Crash

If you’d like to avoid the caffeine crash, we don’t blame you. Here are some ways you can avoid drowsiness and keep your energy throughout the day.

Stick to Morning Caffeine

Caffeine dependence and sleep deprivation can create a vicious cycle. To avoid this we recommend drinking your regular coffee in the morning before 10 AM. This way, you have a higher chance of the caffeine wearing off before it’s time to go to sleep.

Of course, we also recommend sticking to one or two cups of coffee. While you can drink up to four cups without getting the caffeine jitters (depending on your tolerance), keeping it simple is the best way to protect your energy.

Try Some Tea

If you still want to consume caffeine in the morning, try some matcha! Matcha is made from green tea leaves and a single cup contains more caffeine than a shot of espresso.

Plus, matcha also contains an amino acid called l-theanine. This amino acid works alongside caffeine to help improve your brainpower while promoting relaxation and helping to prevent feelings of stress.

Final Thoughts

Coffee is well-known for its energy-boosting effects, but these same effects can also leave you feeling more tired than when you started. This can be because of stress, blood sugar levels, and even less than optimal hydration. Whatever the case, your coffee consumption might actually be furthering the issue.

Luckily, you can avoid this caffeine crash by keeping coffee out of your evenings or by swapping it out for some tea. If you don’t know which teas to try, check out our monthly tea subscription! Simply tell us a little about your preferences, and we’ll send a box of our handpicked recommendations every month. No hassle, no coffee-related caffeine crash, and all delicious goodness.

Interested in trying these teas and others? Subscribers receive 4 teas chosen just for them in every box. Learn more about our tea subscriptions.

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Sleep and Caffeine | American Academy of Sleep Medicine 

Why Coffee Can Make You Tired | Sleep Foundation 

Pharmacology of Caffeine: Caffeine for the Sustainment of Mental Task Performance | Institute of Medicine (US) Committee on Military Nutrition Research

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