Regular, deep breaths provide cells with the oxygen they need to create energy more efficiently. "As you breathe in, let your abdomen pouch out," says Susan M. Lark, coauthor of The Chemistry of Success, $13, www.amazon.com. "Then push the air out from the bottom of your stomach to the bottom of your lungs." Since few of us rarely breathe deeply enough, Lark recommends getting up from your desk twice a day for a five-minute breathing break.