There are different types of yoga classes and if you are a beginner in yoga you must look for a beginner’s class. Do not ever start with advance yoga classes. You should also look for the type of yoga classes that are being conducted which are suitable for stretching and relaxation.
You need to know where you want to take yoga classes. If you are looking for fitness through yoga then you can join a yoga class held at a fitness facility. If you are looking to be a yoga expert yourself then you should look for a place which is solely dedicated to yoga classes only and possibly teaches the "higher" or mental yogas.
If you are having any physical handicap or respiratory problem it is advisable to get yourself medically examined. Even if you are not having any disability, medical check up is advisable before undertaking any yoga classes. Yoga, which is more than 5,000 years old Indian tradition, has become immensely popular in the United States of America. Americans have discovered the art of relaxation through yoga.