The Four Macros of Optimal Sleep: "QQRT " ™

This is from the website of the person who is considered the foremost sleep expert in the world, Dr. Matthew Walker. He has written the book Why We Sleep, and has come up with the QQRT acronym to quantify the quality of our sleep.

While simplistic, one way (of many ways) to think about the question of, “What is good sleep?“, is: good sleep has four main macros. Most people have heard about the three main macros of food (protein, fat, carbohydrate). For sleep, there may be four main macros, which you can remember using the acronym, QQRT™: 1) Quantity, 2) Quality, 3) Regularity, and 4) Timing. This page describes these qualities in greater detail.