Clothing that binds you from stretching should not be worn, as they restrict your free movement. In addition, make sure that the clothes you are choosing are not too tight to hinder your poses, and not too loose to expose your body to others.
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It is recommended to select clothes that are made up of cotton, as cotton gives proper ventilation to your body. In addition, it is also a good absorbent that will eventually help one from keeping the sweat off your body.
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Fitting tops and bottoms are preferred to dress up for Yoga. Usually people prefer to choose Sport wears, and it is better to choose snug fitting clothes. They will help you move freely during your Yoga practice, and will also help not to expose your hidden parts of the body to others.
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Always pick your clothes on what type of Yoga you want to practice. Tracksuit or sweatpants are perfectly fine for practicing Yoga in an air conditioned room, but lighter tops and bottoms are recommended for practicing Bikram Yoga, which is practiced in a heated room.
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