If your optimal amount of sleep is eight hours per night and you routinely sleep seven hours, you may feel okay and be able to function fairly well during the day. It’s only when something in your life changes (perhaps a new job with a shorter commute) that allows you to get an additional hour of sleep that you realize how much better you could have felt and functioned all along. Similarly, runners often need to experience what low-intensity running really feels like before they realize how hard they normally work when they run and how much it’s been hindering their progress.
