From an evolutionary perspective, you’d think stressful experiences would require high alertness. But sometimes, stress means going to sleep.
One relevant situation you’ve probably experienced—and that you share with a lot of the animal kingdom—is the overwhelming snooziness that comes with fighting off an infection. In some creatures, even overheating triggers a nap. And for certain people, the stress of an argument can send them to slumberland, a take on “fight or flight” that seems to make little sense in terms of survival.
Scientists have studied such stress-induced sleep, which is different from the circadian sleep we indulge in every night, in rabbits, mice, and even roundworms, in search of an explanation for why this happens. Now, a new paper in the journal Genetics reports an intriguing finding: A gene that helps repair damaged DNA is involved in putting roundworms under when they are stressed. This implies that at least during some types of stress-induced sleep, the body may be patching up its genes.
In the experiments, a group at the University of Pennsylvania exposed the roundworms to ultraviolet radiation, or UV. They were inspired to try a form of radiation because they had learned that radiation therapy makes patients tired, says Hilary DeBardeleben, a visiting professor at La Salle University who performed the work when she was a postdoc in the lab of David Raizen. Indeed, a dose of UV put the worms to sleep for a couple hours.