Why drinking too much caffeine actually makes you tired

Would you describe yourself as a coffee fanatic? Maybe so, if you not only need that morning cup of joe before you can even bear to open your eyes all the way, but you also consider Mr. Coffee to be the one true love of your life. If only there was a way to make him more portable, so you could bring him with you everywhere you go! Luckily, you've always got your side dude, that money-grubbing companion of yours, also known as Starbucks. He'll give you what you need throughout the day (and in some areas, well into the night), although you're painfully aware he comes at a much higher price than the coffee maker faithfully waiting in your own kitchen.

You already know that your coffee addiction may be having a negative impact on your body as well as your wallet — Eat This, Not That! lists several unpleasant side effects from drinking too much coffee including anxiety, jitters, nausea, and diarrhea, while the Mayo Clinic notes that unfiltered coffee has been linked to slightly increased cholesterol levels. One side effect often associated with coffee consumption is something you might not expect: counter-intuitive though it seems, there are times when drinking a lot of coffee may, instead of causing you to feel wired, make you feel like you need a nice long nap.

What makes coffee act so contradictory?

As Healthline explains, the caffeine in coffee blocks a central nervous system chemical called adenosine that regulates the body's sleep/wake cycle. While caffeine prevents the brain from receiving adenosine, it doesn't stop the body from producing it. Once the caffeine wears off, the adenosine hits all at once, which sends a signal that it's sleepy time.

Another way in which coffee could make you feel fatigued is because it dehydrates you. While yes, coffee is a liquid, it's also a diuretic, meaning it makes you pee a lot. When your body is short on fluids, your heart rate increases, your blood pressure drops, and you start to feel sluggish. If you try to counteract this effect with more coffee, you'll become even more dehydrated, leading to a vicious cycle. If you can try to adopt a policy of alternating water or other non-caffeinated beverages with cups of coffee, this will at least help you stay hydrated, and may help you to stay more alert as well.