Everybody's doing it. Celebrities, seniors, young adults, teens and young children. Even cats and dogs. People of every race and religious group are catching on to the benefits of yoga.

The 5,000-year-old practice has gone from an obscure Eastern-oriented discipline to somehow, almost overnight, the hottest exercise trend.

In 2007, Americans spent $5.7 billion on yoga classes and products, including equipment, clothing, vacations and media, according to the Yoga in America study released by Yoga Journal. The 2008 study indicates that 15.8 million Americans practice yoga. Fitness studios and gyms have seen class sizes swell to capacity as students pour through the doors with rolled-up mats tucked under their arms.

Yoga is a mind-body form of exercise and the benefits are extensive. Not only does it affect the physical aspect of the body, it addresses the mind and spirit as well. Students focus on what they are feeling in their mind and body as they stretch, breathe and place their bodies in various poses.

"It puts you in a good place," said Kay Silk, of Sylvania, Ohio. "The relaxation leaves you with a good feeling to go into the rest of your day."

Pop stars such as Madonna and Sting swear by yoga as the key to a great physique. The various stretches and poses require extensive muscle use and promote increased strength, which leads to toning, all while burning calories and increasing flexibility.

The slow pace and low impact of yoga appeal to people looking

Silk first started the practice when she was in her 30s, but dropped out because the class was too "slow." Now at 75, it's exactly what she wants.

"At some point, you have to slow down," said Silk, a museum volunteer who has been practicing yoga consistently for about six years. "This is slow. You can hold the positions. You move at your own pace. You only do what you're comfortable doing."

While many yoga poses look difficult and intimidating, simple movements such as smiling and reaching for the sky during that morning stretch are forms of yoga, said Mike Zerner, a yoga instructor in Toledo, Ohio.

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