In order to raise breast cancer awareness and inform women about the dangers of wearing a bra, the world celebrates The National No Bra Day on October 13th. Bra has been invented with the idea of holding the breast in place, and is a necessity for women with big breasts. But, recent studies suggest that the bras do more harm than good.
A long-lasting study (15 years) about the negative effects of bras was conducted by Jean Dennis Rouillion, a professor and sports science researcher at the University of Franche-Comte. He performed the study with 330 women aged between 18-35, who were wearing a bra from their early ages. The results were scandalous: bras didn’t do anything to support the chest, reduce back pain or prevent saggy breasts. Actually, wearing a bra made them even saggier! The women who refrained from wearing the bra during the study had a 7 mm. lift in their nipples.
Professor Rouillion thinks that bras cause poor circulation, and that women who don’t wear them can expect better elasticity due to an increase of collagen. So there you have it girls – not wearing a bra is actually better for you.

source: http://speakforum.com/viewtopic.php?f=6&t=598&sid=c25415aae14425c93ae7a667a3f461f3