Don't underestimate the value of sleep. Like proper nutrition and excericise, it is essential to feel our best. Without enough sleep, our senses dull and productivity decreases and mistakes and accidents are much more likely to occur. A study performed by reserachers at St. Luke's Medical Center in Chicago suggests that the more REM sleep that we get, the more likely we are to awake feeling positive and upbeat. A better sleep, boosts the immune system, rejuninates the body, improves memory and motor activity.