Yoga in an air-conditioned gym is hard enough for someone whose life goal is touching her toes. But yoga in a 105- to 110- degree room? I was expecting the worst.

The hot yoga Web site enhanced my fears. “Demanding,” it said, “26 postures” and “90 minutes.” Don’t eat at least three hours before class, it said. Don’t worry about feeling dizzy or light-headed, it added. And moaning, laughter and sometimes tears? Unavoidable.

But the women are encouraging on a recent day at the front desk of Bikram’s Hot Yoga, officially Bikram’s Yoga College of India, Renton, Inc.

“You are in charge of the difficulty,” they tell me, and then say to lay down if I feel sick. They hand me a rubber mat and a large blanket to lay atop the mat, for my sweat. Then I enter the room. The dense heat greets me. The heater whirs. The door shuts and I am trapped in an indoor desert. Resist the urge to run away, I had been told.

Resist I do. I lay on my back, feet pointing toward the windows as instructed (Bikram Yoga says its disrespectful to let teachers see the bottom of your feet). I give in to the heat. The class hasn’t started and I am already sweaty. And hungry.

I’m sure the 16 people around me feel similar. Or at least my workmate. We are two of three beginners.

“Is the air conditinoning on yet?” my workmate asks me.

It isn’t. We don’t get a heat reprieve until the door opens at the class’ end. In between we have 26 postures to complete, with names like half moon, eagle, camel, half tortoise and awkward.

First is a breathing exercise, a preparation for the next 90 minutes. We inhale air for as long as we can, sounding like sirens winding up.

“Just like bellows,” the instructor says.

The instructor walks among the students during the class, giving constant directions. I am too focused on balancing on one foot and pressing my face to my mat to pay much attention, except when she calls my name, which seems often.

While laying on our sweat-drenched mats after one of the more challenging poses, we are told it’s OK to feel nauseous or dizzy. In fact, it’s good. And if we feel like crying or laughing, let loose. I don’t feel any of the above. I just feel hot — intensely hot.

We wind down with a final breathing exercise, in which we exhale puffs of air like an eye doctor’s glaucoma-checking machine. The last pose is called corpse — a fitting end to the class. We lay on our backs, arms and legs outstretched. This is what our bodies wait for every time, we’re told. Lay here as long as we want, up to five minutes.

I’m happy to comply. My heart is pounding in my chest and ears. My body is coated in sweat, like a slimy layer of skin. My tank top and shorts feel like I wore them into a pool. But after a few minutes, I feel good. My head is empty, and the constant ringing in my ears is gone. I feel even better after a shower in the women’s locker room.

Like the front-desk women, these women are encouraging. They congratulate me, the new girl, for making it through alive. You just do what you can, they say. It will come.

The health benefits make me want it to come. The heat brings much of the benefits. As the Web site says, the heat warms muscles, prevents injuries, allows for a deeper workout and flushes toxins from the body. Yoga also “leads to increased mental clarity and reduced stress,” the Web site says.

My instructor says Bikram’s yoga is a whole-body workout, head to toe, A to Z. Each session burns 700 to 1,000 calories. So eat a good dinner, she says.

Annette Petrilli started Bikram’s Yoga College of India, Renton, Inc., six years ago. She started doing hot yoga only two years earlier, at a Fremont studio. She’d never done yoga before.

“I was doing the class, and I could not do anything,” she recalls. “I’m just not flexible at all.”

The heat and the funny smell made hot yoga challenging. But Petrilli says she just did the best she could. She loved the result, and soon knew she wanted to open her own studio.

“In the end I just felt so good,” she says. “I was mentally relaxed, physically relaxed. I just started going every day. I loved it.”

The birth of Petrilli’s daughter has made her scale back to two to three hot yoga practices a week. Petrilli’s work opening a new studio in Kirkland has also cut down her teaching, from 15 of 21 weekly classes to just one of nine classes. Six teachers back Petrilli at her Renton studio.

Any type of yoga is a life-long practice. But it took Petrilli six months to a year to get down the correct form. Some of her students are much faster.

Her students range from 20 to 80, and have every level of fitness, ability and job.

“It’s a complete mix of people,” Petrilli says.

The number of students she has taught is in the 4,000s, some with her since the beginning. Summer classes typically have 15 to 20 students, winter 25 to 30.

“It’s good all year long,” Petrilli says of business at her Renton studio. “It’s definitely been a process, no doubt about it. While I wanted it to be an overnight success, it certainly wasn’t. Like a lot of businesses, it took time and work.”

“But I love where it is,” she adds. “And I love where it’s going.”

Hot yoga

Bikram’s Yoga College of India, Renton, Inc., is at 339 Burnett Ave. S. A variety of payment options are available. Classes are every day. For more information, call 425-204-5038 or visit www.bikramyogarenton.com.

Bikram Yoga was developed by Bikram Choudhury of India and is suitable for all ages and levels.