Business is booming at Kaia Yoga in the posh Connecticut suburb of Westport.
Enrollment at the five-year-old yoga and juice bar chain has jumped each year during the economic downturn, even as students have cut spending in other areas of their lives. Many of the new students are men who are trying to reduce the stress, says co-owner Gina Norman.
"In these economic times people either go to yoga studios or bars," says Norman, only half-joking. Classes in calming types of yoga, such as yin yoga, are especially popular she says. "It's mostly about the stress reduction."
Yoga has seen a sharp jump in the past three years, and now has about 14 million practitioners, compared with just 11 million followers three years ago, according to market research firm GfK-MRI.
Bill Harper, Yoga Journal's publisher, says the ancient practice has been gaining traction steadily over the past decade, but that the financial crisis offered a bit of a boost.
"When we get into shaky financial times and people are feeling bad about themselves, they seem to turn to yoga for a bit of solace," he says. The magazine is now able to attract mainstream advertisers, such as Procter & Gamble and Ford Motors, who in the past may have avoided associating themselves with "downward dogs."
Dozens of companies have piled on for a slice of the market.
Lulu Lemon, a Canadian company founded just 12 years ago, now makes $500 million a year selling lycra pants and rubber mats that are "yoga inspired," according to its tagline. Colorado-based Gaiam now sells $285 million a year worth of balance balls and sanitizing wands to yoga devotees. Clothing giant Gap bought yoga wear maker Athleta a few years ago, and upscale gym chain Equinox is about to launch yoga teacher training.
Recent numbers on revenue growth are not available, but Yoga Journal reported in 2008 that Americans spent $5.7 billion on yoga classes and equipment (including clothing, DVDs and mats), almost twice as much as they did in 2004.
Most of the growth, however, isn't coming from large corporations. It's coming from small businesses, like Kaia, which have sprouted across the country. Many of the entrepreneurs who have opened yoga studios – often with training centers, health-food bars and retail sections that sell clothing, equipment and jewelry – are yoga devotees who have left behind other careers.
Lizzie Clark, owner of Bikram Yoga in Charlottesville, part of a national franchise founded by yoga mogul Bikram Choudhury, worked as a legislative assistant for a US senator before deciding that she wanted a career with a healthier lifestyle.
"It's a great business opportunity," she says. "You're not going to become a millionaire doing it, but you're going to live a lifestyle you believe in."
As the industry grows, however, more business owners are finding a way to earn millions. Bikram Choudhury, who popularized so-called "hot yoga" in the US, is considered one of the country's most successful yoga entrepreneurs.
In 2003, Choudhury caused an uproar when he copyrighted the 26 sequences that make up his distinctive form of yoga, practiced in 105 degree heat. Over the years, courts have sided in his favor when the copyright was challenged. Choudhury has also set up a franchise that now oversees hundreds of studios around the world and whose owners must each be re-certified every three years.
A representative of Bikram's Yoga College of India, the Los-Angeles-based parent company, tells ABC News.com that Choudhury is out of the country and not immediately available for comment.
Other popular yoga masters have since followed his lead. There's Baron Baptiste, who introduced "Power Vinyasa Yoga" and now runs bootcamps and teacher certifications around the country. There's John Friend's "Anusara Yoga." There's Duncan Wong's "YogicArts."
"When you get to be a teacher at the mega yogi level, and you're selling DVDs and books and charging thousands of dollars for appearances, you are basically a yoga corporation," says Neal Pollack, author of the upcoming book "Stretch: The Unlikely Making of a Yoga Dude." As such, these entrepreneurs have little choice but to sue when others try to steal their techniques. "That's what corporations do to protect their business interests."
Others disagree. There's a large contingent of yoga devotees who believe they more closely follow the practice's ancient tradition of ascetism and spirituality. They are the ones who argue that yoga wisdom should not be trademarked, since yoga only exists today thanks to a tradition of teachings passed on through the generations.
In a New York Times op-ed a few years ago, the Indian-American writer Suketu Mehta pointed out that "yoga" means "union" in Sanskrit, and that Indians believe in a universal mind that all human beings can tap.
"It's a mystery to most Indians that anybody can make that much money from the teaching of a knowledge that is not supposed to be bought or sold like sausages," writes Mehta. "Should an Indian, in retaliation, patent the Heimlich maneuver so that he can collect every time a waiter saves a customer from choking on a fishbone?"
Among mainstream US yoga experts, however, most seem to defend entrepreneurs' rights to profit from customer demand. They point out that many Americans practice yoga as a form of exercise, not as a path to spiritual enlightenment and that anyone who does prefer a more ascetic form can easily opt out of the commercialized version.
Says author Pollack: "As with anything, you have people following it for altruistic purposes, and others for capitalist intentions. Just because it helps people in the aggregate doesn't mean it's exempt from the dark side of human nature."