In the business-book section of Japanese bookstores, a spine reads "Kyuyogaku" — literally, "the study of rest." Not exercise science, not nutrition science: rest as an academic discipline. Published in 2024, the book has become a bestseller with over 160,000 copies sold. A book about resting, selling next to books about working — that sight alone says something about how tired this country is right now.
"Kyuyogaku" is a discipline that started with one person
The author of "Kyuyogaku: Saving You from Fatigue" (Toyo Keizai) is Hideki Katano, a doctor of medical science and the representative director of the Japan Recovery Association. Every year, the association runs a large-scale survey of fatigue among working people nationwide; in the 2025 edition, 46.3% of workers reported being frequently tired. We cited that number in the active rest article as well — and the person at the center of that survey and advocacy work has now organized how to rest into a single "discipline." That's the book's position. The reason it sold is plain: everyone is exhausted, and nobody was ever taught how to rest.
Rest isn't one thing. "Sleep" is only a fraction of it
The core of the book is its classification of rest. It divides rest into three categories — physiological, psychological, and social — and further into seven types: repose, exercise, nutrition, connection, entertainment, creation/imagination, and change of scene. Sleeping and lying down are "repose." Moving lightly to keep circulation going is "exercise." Time with people you're at ease with is "connection." Losing yourself in a hobby is "entertainment," making something with your hands is "creation/imagination," and changing your environment to reset your mood is "change of scene." Seen through this framework, most people's days off skew entirely toward the "repose" type. Lounging and streaming use just one-seventh of the menu. If you're tired and still groggy after the weekend, what's missing may not be the quantity of rest but the variety — and this, we think, is exactly what classification is for: producing that kind of realization.
Incidentally, beyond the book, the Japan Recovery Association also works on rest education through a certification program for "rest specialists" (kyuyoshi). Resting becomes a book, then a credential. A development that would have sounded like a joke a few years ago is proceeding with a straight face in an exhausted country.
So what was new about this book? In our reading, it comes down to one move: redesigning rest from "a repair job you do after depletion" into "something you stock up in advance." Not collapsing into sleep after you're spent, but scheduling rest before the fatigue arrives. Resting on offense. For hard workers prone to guilt about resting, this reversal of sequence supplies the logic that changes behavior.
Put two different types of rest on your next day off
- On your next day off, schedule two rests of different types. For example: light movement at midday (exercise type), dinner with someone at night (connection type)
- Reverse "rest after you're tired" — just once. The day before a big piece of work is exactly when to rest early, on purpose
- Count which type of rest you always default to. Just noticing the skew changes how you design your next day off
What's written here is not the whole of the book. If it caught your interest, go to the source.
