It would help, if you knowing what you shouldn't wear. Don't wear anything that will restrict bodily movements. The obvious items including jeans, dress shirts will not allow the body to relax and breathe freely. As simple as it is, make sure that you take the time to use the proper clothing. Here are some things to look for in good clothing choices for yoga:
Loose-fitting is good- Form fitting clothing restricts the blood flow inhibits the correct breathing techniques. You should be able to able to perform various yoga poses. Try yoga shorts, sweat clothes, leotards or yoga pants.
Sweat absorbent- Lastly, there are some clothing options that are excellent. For example, the materials that they are made of are able to absorb sweat and keep it away from the skin. Look for specific yoga clothing selections for these.
Comfortable- You should be comfortable wearing whatever you choose. Since the objective is to relax you should never be worried about what you look like.
Yoga shoes/socks?- In some studios you are allowed to wear yoga shoes/socks. You should inquire ahead of time to be better prepared.
Just make sure your clothes fit your personal style and you'll be able to keep your mind on what you were there to do in the first place ? Practice Yoga!
