Tired After Coffee: Why the Drink Sometimes Doesn’t Wake You Up

That you are not awake after a cup of coffee but tired may sound counterintuitive. After all, we drink coffee to wake up. In this article you will find out why the caffeine boost sometimes turns into its opposite.

Tired after coffee – that’s behind it

The main reason why coffee doesn’t always wake you up, in fact the opposite, is the interaction between adenosine and caffeine.

• Normally, caffeine has a stimulating, concentration-enhancing and alertness-enhancing effect. To develop this effect, caffeine docks onto adenosine receptors and blocks them.
• Adenosine is considered a caffeine antagonist: In contrast to caffeine, adenosine has a calming effect, lowers blood pressure and ensures that the release of certain messenger substances that have an activating and invigorating effect is inhibited.
• If you regularly consume a lot of coffee, this leads to two things: On the one hand, the adenosine receptors lose their sensitivity, so that the caffeine can no longer dock easily and develop its waking effect.
• On the other hand, your nervous system increasingly forms new receptors, which means that relatively speaking more adenosine can dock again, which reduces the effect of caffeine and, in return, increases the calming, sleep-promoting effect of adenosine.

More reasons why coffee doesn’t wake you up

In addition to the interplay between caffeine and adenosine, there are other factors that can negatively influence the stimulating effect of coffee.

• Dehydration: Coffee has a diuretic and therefore indirectly dehydrating effect if you don’t drink enough fluids. Dehydration can make you feel tired and listless despite coffee.
• Too little sleep: A study from 2021 was able to show that caffeine loses its waking effect when you are sleep deprived and overtired. If you don’t sleep enough, you will remain tired even after the cup of coffee.
• Genetics: In addition to the habituation effect described above, there may also be genetic reasons why coffee does not wake you up: In some people, the caffeine is broken down more quickly or the adenosine receptors are less sensitive from the start.
• Our tip: In order to benefit from the positive effects of caffeine, you should drink less coffee overall to prevent you from getting used to it. If you stay abstinent for a long time, the coffee will work as it should again.