By MICHELLE BOORSTEIN, Associated Press Writer

NEW YORK - Heated to precisely 105 Fahrenheit (41 degrees Celsius), the Bikram yoga studio is so hot the windows look like it's raining — inside. And then there are the 25 very sweaty bodies, all trying to stretch themselves into increasingly strenuous positions as the teacher calls out an occasional: "Don't panic!"

  Sometimes they do, bolting from the carpeted sweatbox for a few minutes respite in the hall.

"The smell is intense in there," says one man, guzzling water and pacing the corridor before heading back inside to finish the 90-minute class.

To some who practice yoga, there is something far more offensive at the Manhattan studio than the heat or stench. To them, this newfangled yoga represents the biggest threat the spiritual discipline has faced since people began practicing it more than 5,000 years ago in India, fasting, abstaining from sex and meditating in search of higher consciousness.

They fear that the discovery of yoga by millions of Americans in recent years is killing its soul, distorting the purpose from pursuit of a better self to pursuit of a better butt.

Among the things that scare them: dlrs 38 skimpy "chakra" tanktops, disco yoga and a Web site called "Yogasm: Where Yoga Meets Fashion." Car advertisements that show a person meditating in front of an SUV. Aerobics teachers who take two-day yoga courses that supposedly prepare them to do a job intended for spiritual gurus. Yoga golf.

Now a movement is afoot to return yoga to its more traditional roots. To replace sweating with meditation, hip hop with silence. To supplant Madonna as the face of yoga with people more the likes of Patanjali, the man who standardized the ancient philosophical texts about 800 years ago.

"When yoga was in its womb in India, it was safe and protected, but as it ventures into the harsh world, it is in danger of disintegrating," said Dr. Scott Gerson, a prominent alternative medicine expert and internist in New York who has practiced yoga since the 1970s. Gerson refers to most of the newer yoga classes as "debauchment."

Yoga holy warriors like Gerson are calling for a return to teaching yoga in its original form, a program aimed at seeking self-enlightenment by training the mind. The physical postures, or asanas, most people think of as yoga are just one segment, and were meant to be part of a yearslong path of study that includes practicing non-violence, restraint and meditation.

In the past decade, however, yoga has been vigorously Americanized, repackaged and remarketed and spit out in a multitude of images, primarily one with a hard body. It is now taught everywhere from hip city gyms like Crunch on Miami's South Beach to grimy basement studios on Manhattan's Lower East Side to the Monroeville, Pennsylvania, Senior Center, where class meets right before quilting and pinochle.

According to Yoga Journal, the industry's biggest magazine, 15 million people practice yoga in the United States, up from 12 million in 1998. In that period, the magazine's circulation nearly tripled, to 250,000.

A frequent target for yoga purists is the genre practiced by Bikram instructor Raffael Pacitti, a popular form known as "hot yoga" because it calls for 90 minutes of deep stretching in a heated, carpeted room. Founder Bikram Choudhury, a childhood yoga champion in his native India who now lives in Beverly Hills, California, says the heat means it is easier to stretch. It also means the air smells like a massive pile of soiled gym clothes.

"The most exciting, hardworking, effective, amusing and glamorous yoga class in the world!" promises the Bikram Yoga Web site.

The fear of purists is embodied in the locker room at Bikram, where one sweaty young woman finished the class and exulted, "I could die right now and be perfectly happy."

Most of the women leaving Pacitti's class don't know that classical yoga often has little to do with stretching, and certainly not with strenuous positions or movements fast enough to make you sweat.

Maty Ezraty, who runs a popular yoga center in Santa Monica, California, sounds heartbroken when she talks about Americans' "physical addiction to sweating" and how she feels it is afflicting yoga.

As a longtime yoga practitioner, Ezraty feels she is seeing a profound philosophy and lifestyle reduced to nothing more than an alternative to step aerobics or kickboxing. But as a businesswoman, she knows she can't fight the market.

At YogaWorks, Ezraty offers the athletic style Ashtanga, or 'power yoga,' as well as meditation and deep breathing.

"Senior people are looking in awe at these sweat classes, and it's really sad," she says. "But it's a real dilemma, because these workout classes are so popular — there's no stopping them. Yoga teachers who see yoga as more than exercise are caught."

The bandwagon of those cashing in on yoga's popularity is crowded. It ranges from YogaFit, a company that trains teachers over a single weekend to individuals like Alan Ripka and Ashok Wahi.

Last year Ripka, a Manhattan lawyer, opened a yoga center whose classes are broadcast live on the Internet. It caters to businesspeople too busy to leave their office and stay-at-home parents. Wahi, a mechanical engineer and longtime yoga practitioner from Hillsborough, New Jersey, designed a 9-minute program specifically for golfers. He began selling it last year.

Wahi brushes off criticism about the mainstreaming of yoga. "It's like math vs. applied math; my approach is applied yoga."

John Tunney understands that middle ground. A yoga teacher and founder of one of the biggest yoga information Web sites — www.yogasite.com — Tunney sees everything from new teachers ignorant of basic yoga terminology to those who want to know if yoga can reduce knee flab.

While he understands purists' desire to aim for total self-realization, Tunney thinks it may be unrealistic to create the ideal cocoon in busy American life.

"I treat it as a spiritual discipline, but that doesn't mean I expect to be a long-bearded swami sitting on a mountain. For me, yoga is about being in the world." That said, he thinks the spiritual benefits of yoga sneak up on even those on a quest for a toned tummy.

"The thing about yoga is that it works whether you believe in it or not," said Tunney, of West Orange, New Jersey.

Regardless, the movement to revive yoga's classic principles is on.

The Yoga Alliance, a group of prominent yoga teachers, launched a formal registry of trained teachers in 1997. Teachers who have the alliance stamp must have at least 200 hours of training, including 30 hours of philosophy and their own teacher — something closer to the ancient system of apprenticing.

Even in mainstream Yoga Journal, an ad reminds readers: 'Asana is just the beginning,' while a letter to the editor asks why the magazine uses photographs of women who "look like they belong in Cosmopolitan." The author closes with: "I wonder what the ancients would think of this?"

Concern about the future of yoga is also coming from the home of its past, India.

Several prominent conferences there in recent years have focused on how to bring yoga back to its roots. Subodh Tiwari, administrator of the Kaivalyadhama Yoga Institute in Lonavala, India, said leaders from most different yoga wings agreed in 1998 to promote yoga in its authentic form.

"We can't modify yoga to suit persons, because persons have various personalities and we can't change it according to each and every person," he said from Lonavala.

Tiwari said the practice of newfangled, sweat-oriented yoga has bounced back overseas to India.

At the Chicago branch of Sivananda, one of the most traditional yoga schools, director Chandrashekara is reluctant to criticize the new yoga classes. After all, he says, "being judgmental isn't good for our health."

However, he offers his opinion in an apt metaphor: "To call these classes yoga, it's really a stretch."