Better Than Before: What I Learned About Making and Breaking Habits--to Sleep More, Quit Sugar, Procrastinate Less, and Generally Build a Happier Life

by Gretchen Rubin

Sleep, as I remind anyone who gives me the opportunity, is crucial for good mental and physical health and a critical time for bodily repair and regulation. Lack of sleep negatively affects mood, memory, immune function, and pain sensitivity; it makes people more likely to fight with their partners; it contributes to weight gain.