SANDPOINT – When the pressures of her job as a software designer for American Airlines caught up with her, Darcy Chambers would check herself into a chi-chi Dallas spa. "Fix me," she'd tell the masseuse and the manicurist. At the end of the day, she'd emerge – kneaded, polished, relaxed and ready for another round of 12- to 14-hour workdays. Today, Chambers is part of the $15 billion U.S. spa industry. She runs Heaven – the Spa in Sandpoint, selling wellness, relaxation and beauty treatments to other overtaxed professionals. Visiting a spa is one of the fastest-growing leisure activities in the United States. More than 130 million people, most of them women, will visit a spa this year, according to industry statistics. Over the last decade the number of U.S. spa facilities has quadrupled, to more than 12,000.