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Everyday Science · Coffee Caffeine

Why do coffee keep you awake?

A woven basket filled with roasted coffee beans sits on a dark wooden table.
ProtoplasmaKid. CC BY-SA 4.0. Original.

The short answer

Coffee keeps people awake because caffeine acts as an adenosine receptor antagonist1. It is known for its stimulant effects1. Historically, Sufi mystics in Yemen used coffee to stay awake for nocturnal vigils3. During the celebration of Ramadan, coffee helped people stay awake at night and fast during the day2. While it was regarded as excessively stimulating in Yemen3, some sources have viewed it as a mind-altering substance similar to alcohol2.

What the evidence shows

Biological Action

Caffeine is an adenosine receptor antagonist1. It is also known for its stimulant effects1.

Historical Usage

Sufi mystics in Yemen were among the earliest social users of coffee3. They used the bean because they needed to stay awake for nocturnal vigils3.

Cultural Context

Coffee helped consumers stay awake at night during the Muslim celebration of Ramadan2. It also helped these consumers fast during the day2.

Our take

This part is our own interpretation, not a sourced finding.

It is fascinating that coffee was once viewed as a mind-altering substance like alcohol2. This historical perspective highlights how deeply its stimulating effects have influenced human culture3.

What we can't say for sure

The sources do not provide a complete explanation of caffeine content1, nor do they specify the biological mechanism of how coffee keeps people awake2.

Sources

  1. Authority control databases. Coffee - Wikipedia. en.wikipedia.org. other website, accessed 2 November 2026.
  2. History of coffee - Wikipedia. en.wikipedia.org. other website, accessed 2 November 2026.
  3. Turkish coffee - Wikipedia. en.wikipedia.org. other website, accessed 2 November 2026.

Published 2 November 2026. Sources last checked 2 November 2026. Prepared with automated tools and checked against the sources named here: how we work. Spotted a mistake? Tell us.

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