Science of slumber

Science News has a brilliant special issue on the ‘science of slumber’ that tackles sleep disorders, the mental impact of sleep deprivation, how sleep differs across species and the still mysterious question of why we need to sleep.

I found the article on two seemingly straightforward sleep disorders, insomnia and narcolepsy, the most interesting. They seem straightforward because they appear as a lack and an excess of sleep, but as the piece makes clear, they are still quite mysterious.

Insomnia is particularly interesting because having trouble sleeping happens to everyone at some point, so in itself, it’s not abnormal – meaning that research into what triggers it is unlikely to find anything striking.

Instead research has shifted to try and understand what prevents insomnia from resolving naturally so it becomes a chronic condition:

Sleeplessness may be brought on by traumatic events such as a death in the family, an illness such as cancer or anything else distressing, causing a person to lie awake at night with a racing mind. For a subset of people, though, insomnia has no prompting signal — a condition called primary insomnia.

Regardless of the trigger (or lack thereof), temporary insomnia has a nasty way of becoming a habit. Poor sleep habits can become ingrained. When trouble sleeping persists for three or four nights a week over several months, insomnia is considered chronic.

It may turn out that untangling the prompting signals of insomnia, as many sleep researchers attempt, is a fool’s errand, says Michael Perlis, director of the University of Pennsylvania’s Behavioral Sleep Medicine Program in Philadelphia. “The whole zeitgeist has changed,” he says. Most sleep researchers now agree that “once insomnia goes chronic, it stays that way,” regardless of the prompting signal, Perlis says. So rather than focusing on the immediate trigger for insomnia, many scientists are trying to figure out why it becomes chronic and how to prevent that from happening.

I also liked the short piece that briefly compares the amount of type of sleep between lots of different animals. It seems dolphins don’t have REM sleep. I wonder if that means that they lack or have very limited dreams?

Anyway, a great collection of articles and all freely available online.

Link to SciNews ‘Science of Slumber’ collection.