If you practice any type of yoga, there’s a chance you’ve heard of a yoga (or Mysore) rug. These thick, cotton, mat-sized rugs are essential to sweaty yoga classes, like Bikram or Ashtanga. But these rugs aren’t a new fad of yoga, they’ve been around for decades and have tons of benefits.
Ashtanga Yoga was systematized by Pattabhi Jois, who started his yoga foundation in Mysore, India. These cotton rugs, were recommended for the early morning classes, because of the high temperatures of south India, to soak up the sweat and minimize slipping during practice.
A normal yoga mat may give you additional traction but once the floodgates let loose, they become DIY slip-n-slides. The rug can also be slippery when it's dry but there are ways to manage this like spraying them with water or getting stronger (see below).
Your yoga mat is a prop. The stickiness of it stops your feet from sliding out which is most noticeable in standing postures, like down dog. The sticky texture of the popular yoga mat was actually invented by a person who had a medical condition where she didn't sweat so her feet were super slippery! If you don't have this condition then you most likely don't need this prop. It's going to be harder at first to keep your legs together using a rug but that's the point. You are building the strength of a strong foundation.
As yogis, we get very intimate with our mats. We press our faces, bums, palms and tears to our mat and wouldn’t you rather have soft cotton to land on when faceplanting or rubbery plastic? There is really no contest here.