More and more Calgarians are signing up to be karma cleaners, exchanging chores for free yoga lessons. Waiting lists are forming. (J.P. Moczulski/Canadian Press)

A growing number of yoga students in Calgary are paying for classes with their sweat.

The phenomenon of karma cleaning sees wannabe yogis scrub toilets and showers at studios in lieu of paying cash for classes.

Desiree Duigou, like 20 other students at Calgary's Bodhi Tree Yoga studio, trades at least 2½ hours of chores a week for free yoga instruction.

She's still cleaning toilets, but those who reach the upper levels of the karma cleaning hierarchy get easier duty, like doing laundry.

"Yoga can be a very pricey practice," Duigou said.

Studio owner Celeste Needham said yoga classes can be expensive because of the costs of running the studio, such as rent and teachers' salaries. In this regard, she said, it's no different from any other business.

Needham was once a karma cleaner herself, vacuuming and washing mirrors at a Vancouver studio.

"I couldn't afford to go to yoga. And it was something that the studio I went to offered me as an opportunity to still be able to practice and at the same time give back," she said.

"We're really grateful for the people who do this job.… The place always looks so good."

Needham said that her studio keeps finding more karma jobs for students to do and that it seems to be one area of her business that keeps on expanding.

Duigou has been cleaning toilets for more than a year.

"It's kind of off there in the distance," she said when asked about when she will graduate to cleaning towels. "It will be great when it comes available."

Becoming a karma cleaner isn't as simple as just signing up. Bodhi Tree, like many other studios across the city offering the payment option, has a waiting list.