Without energy your brain can’t function properly

Although managing your time is important, if you have no energy, all the time in the world will not get you the results that you want.
Your brain needs large amounts of energy just to carry out its normal functions. It is only about 2% of your body weight but consumes about 25% of the oxygenated glucose and other nutrients carried by the circulatory system.
In addition to its normal job, the brain is asked to concentrate for long periods of time, make decisions, and switch from one task to another while still focusing on what’s important – all of which consume energy. And for the majority of people, it has to do this under stress and with inadequate sleep and nutrition.
Even when you sleep your brain is active, processing information, consolidating memories, and working on problems that have stymied you during the day.
Lack of energy reduces the strength of our executive skills – those brain-based skills required to execute tasks efficiently and effectively. When our brain as tired we tend to procrastinate, become easily distracted, lack focus, show poor judgment, make rash decisions, have little self-control, and are more susceptible to anxiety and stress.
Managing energy presumes you are building enough energy in the first place – through adequate sleep, exercise and proper nutrition. Probably the biggest reason for an inadequate supply of energy is due to a lack of sleep. Sleep has taken the brunt of our need for additional time to do all the things we want to do – to the point where the average recommended sleep time of 7 to 8 hours a night is being short-changed by at least an hour.
People have difficulty believing that spending more time sleeping provides more energy – both physical and mental – to get more things done. But look at the fastest creature on the planet – the cheetah. It can accelerate from 0 to 60 mph in just 3 seconds. But it spends 18 hours a day sleeping!
Assuming you have a sufficient amount of energy in the first place, you can manage it by avoiding marathon work sessions, taking frequent breaks, reducing interruptions, ceasing any attempts to multitask, and eliminating as many sources of stress in your life as possible.
With time, energy, and the habit of planning and proper prioritizing, you will increase your bottom line results.