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Illness & Sleepiness

February 1, 2017

A primitive neural switch may explain why illness makes us sleepy.


Varvara CC BY 2.0, via flickr

(Varvara/CC-BY 2.0, via flickr)


Why sickness makes us sleepy. I’m Bob Hirshon and this is Science Update.

The flu and many other illnesses can make us overwhelmingly sleepy. And according to University of Pennsylvania neurologist David Raizen, it’s not regular fatigue. It comes from a specific sleep-inducing brain circuit that’s triggered by infection.  

DAVID RAIZEN (University of Pennsylvania):

We think that the underlying neurobiological mechanisms  that regulate it are different from the underlying neurobiological mechanisms that regulate daily sleep.


In the journal eLife, he and his team identified a single nerve in the nematode, a type of flatworm, that makes them sleepy when they’re sick, but has no effect on the animals’ daily sleep. Raizen suspects that a similar circuit may occur in humans, and understanding how it works could help him develop treatments for debilitating human fatigue, like that caused by cancer chemo-and radiation therapies. I’m Bob Hirshon, for AAAS, the science society.

Story by Bob Hirshon