“Sleep is much more important than most people realize. Sleep conserves body energy and restores you physically and mentally. Colds, flu, and many other ailments are more common when your immune system is depressed by lack of sleep. High blood pressure is more common in people who get fewer than 7 hours of sleep a night, and poor or reduced sleep increases the risk of heart disease and stroke. Sleep also contributes to healthy metabolism, which helps you maintain a healthy body weight.” (Donatella Di Corrado, 2006, p.53)