Form Follows FunctionIf your hair is shoulder-length or longer, try a hairstyle that keeps your hair off your face (it's annoying) and neck (it's hot). It's also best if you can lie down with the back of your head flat on the mat and get back up again without having to stop and adjust your hair, which will interrupt the flow of the class and probably cause you to miss a pose or two.
For layered hair, a wide fabric headband can pull your hair back from your face. Bobby pins and barrettes are also options, but they can be uncomfortable when you stand on your head. If you have short or bobbed hair, the headband may be all you need. Adding a low ponytail or braid is one option for longer hair. This type of ponytail also offers a nice, professional look, so if you are heading to work after you practice, you can just neaten it up and be on your way.