I can’t remember where I heard about Internal Time: Chronotypes, Social Jet Lag, and Why You’re So Tired but with a subtitle like that, I had to read it.
Unfortunately, as I finished it one morning at 4am (whilst not sleeping), I concluded that the book was more descriptive than prescriptive.
Roenneberg presents a fairly readable account of the science behind sleep. It turns out that people are born with genetic chronotypes making them tend toward being early birds or late owls. The social story is that people who sleep late are lazy (“the early bird catches the worm!” type sayings are common in most languages) but actually they just respond differently to time and light on a cellular level. Roenneberg describes some fascinating studies on how this works.
An especially helpful result of reading this book is that it gives enough information to help readers evaluate things in the popular press regarding sleep. Roenenberg mentions several times how erroneously the press reports on sleep, taking things out of context or blowing things out of proportion. For example, the frequently reported “fact” that having small lights in your bedroom (like a night light or alarm clock) messes with your serotonin production is false.
I’m not sure why the book never makes the leap to discussing what people can DO about the issues and problems it raises. What should people do to overcome social jet lag? How can we manage our chronotypes given that we live in a society that expects us to get to work and school on time? And please, please, what do I do about being so tired???
Although the book was interesting, I have a hard time recommending it because it so lacked conclusions about how to even begin to address these questions. If I had more time (or was not so tired) perhaps I could apply some of the experimental findings to attempt to fix sleep for myself. That would involve things like getting more exposure to daylight, not looking at screens or flourescent lights after twilight, never traveling across time zones except by slow-moving conveyance like ships or bicycles, or perhaps living in an underground bunker without any outside input on when my day begins or ends.
Well, some of those would be easier to implement than others.
If you’re deeply interested in the science of sleep, you might enjoy Internal Time, but if you’re looking for solutions to sleep problems, this is probably not the book for you.
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