"Be short of sleep and your thinking becomes more muddled, reaction times are slower, and your efficiency plummets. You get into a sleep deficit, which has an ongoing bad effect on your health, not just your productivity."
"Regular physical exercise boosts energy levels. It helps heart and lungs to operate more efficiently and will 'deliver oxygen and nutrients to your tissues.'"
"Basic conditions like problems with thyroid or blood sugar levels can affect the amount of energy the body can create. If you haven't had a physical in a while, get one now."