MorePeople Who Exercise May Have Bigger Brains5 Reasons to Skip a Workout, According to a Fitness Expert New to yoga? It can take a few sessions before you fully get the hang of the different poses, not to mention class etiquette. But if you don’t have a clue what the difference is between downward-facing dog and shavasana, then you might spend a good chunk of your first few classes fumbling through your flows.