The percentage of time you spend actually sleeping while in bed.
Sleep efficiency is a beautiful measure of how restorative your nights are. It's not just about how long you're in bed, but how much of that time your body spends in deep, healing rest. High efficiency means you fall asleep easily and stay in that peaceful state all night long.
Rest is when your body does its heavy lifting—repairing muscles, balancing hormones, and clearing your mind. Improving your sleep efficiency is like giving your body a premium 'nightly service' for longevity.