Coffee does not give you energy
Caffeine keeps you alert by blocking adenosine receptors. It does not supply energy to the brain. It hides the signal that you have been awake.
Established2 min read
Adenosine accumulates as cells spend ATP and as waking goes on. At receptors in the brain it promotes sleep pressure. Caffeine sits in the A1 and A2A receptors and does nothing useful there. The sleep pressure is unpaid, not erased.
Tolerance is the brain adding receptors. None of this is a moral against coffee. It is the mechanism, and the mechanism is a mask.
Caveats
- Caffeine has other effects at higher doses. The daily alerting effect is the adenosine block.
Sources
- 1Fredholm B. B., Bättig K., Holmén J., Nehlig A., Zvartau E. E.. Actions of Caffeine in the Brain with Special Reference to Factors that Contribute to Its Widespread Use. Pharmacological Reviews 51, 1999.