It's no secret that there are a million different kinds of yoga out there. There's hot yoga, aerial yoga, prenatal, power, restorative--you name it, it's probably a form of yoga. One thing all yoga classes tend to have in common is the soothing music played during classes to create a relaxing atmosphere. But what about the people who aren't relaxed by this music? Enter Sandman... I mean, enter metal yoga.

A lover of metal music myself, I'll admit that when I first heard that metal yoga was a thing, I was a) pretty mad I didn't start it myself, and b) curious as to how metal could be relaxing background music for a yoga class.

Saskia Thode, founder of Metal Yoga Bones in New York, strives to make every class as intense as possible. She encourages her students to release their anger by yelling, banging on the floor, and howling -- a far cry from the "Oms" and sun salutations you'd probably expect in an average yoga class.

Thode grew up listening to metal music and going to metal music festivals, and she decided to bring her love for the genre together with her yoga practice.

Thode isn't the only instructor who has introduced a darker side to yoga. Kimee Massie, founder of Black Yoga, says she likes to add metal music to her classes to "shake up your chakras, but in just a certain way."

The idea of downward dogging to Iron Maiden might have some yogis feeling uncomfortable, but both Thode and Massie agree that even though it's not the traditional way to practice yoga, it can be just as spiritual for students. Their classes offer a space where people can release their pent up anger while listening to loud, emotional music.

These two instructors have shown that it's okay to break away from the traditional. Because sometimes, let's be honest, screaming and head-banging is needed to release all the stress life can put on us. And as Massie says on her website, "You can't fully appreciate the light until you understand the darkness."