Matthew Walker asserts that quantity, quality, regularity, and timing are the four essential macros for good sleep, with regularity being a significant predictor of mortality.

“In my mind, there are really sort of four macros of good sleep. Three macros of food, fat, protein, carbohydrate. For sleep, four macros. And you can remember it by the acronym QQRT. And it stands for quantity, quality, regularity, and timing.”