Dr. Matthew Edlund, M.D., researches rest, sleep, performance and public health, and is the author of Healthy Without Health Insurance, The Power of Rest, The Body Clock Advantage, and Designed to Last; his previous articles can be found at therestdoctor.com.
Rest is regeneration. "The Power of Rest" shows you how to use active rest - physical, mental, social, and spiritual - to control that regeneration, as well as maximize the effects of passive forms of rest like sleep.
Rest is necessary for survival. Active rest techniques, most of which can be accomplished within 60 seconds, can calm you in the middle of the maelstrom or revive you when exhausted - while improving productivity.