Inside us
Adenosine
One of the chemical signals involved in your growing pressure to sleep.
Adenosine helps link time awake with sleep pressure. Caffeine can interrupt part of this signalling by occupying adenosine receptors.
A closer look
The picture, in three parts.
Time awake
Sleep pressure builds during wakefulness.
Chemical signal
Adenosine is involved in that regulation.
Interruption
Caffeine blocks some adenosine receptor activity.
Where could this take you next?
Sources & further reading +
Short explanations, grounded in published sources. Follow the originals for depth and context.
- NINDS — Understanding sleep ↗ (opens in a new tab)
- National Academies — Pharmacology of caffeine ↗ (opens in a new tab)
Sources checked: 10 September 2026. Visuals are illustrations, not documentary evidence.
Our approach to sources and corrections