Energy, not time, is the fundamental currency of peak performance and value creation. Many people are focused on time management, but eventually you realize that time management doesn't matter if you don't have enough energy. Without the energy to complete tasks, you're beholden to time rather than making time work for you.
As an entrepreneur, you have probably had the experience of putting in 16-hour days, with barely a break for lunch, but still going to bed knowing you didn't create much value. On the other hand, you also may have had the experience of working four hours and knowing you've created more value in this short amount of time than you have working three times this much.
What makes the difference? The difference, of course, is energy--physical, mental, emotional, and spiritual energy. Energy, not time, is the fundamental currency of value creation. Think about how you can optimize your energy, rather than how you manage your time.