Kim Kardashian says she is obsessed with waist training..... Do they really work?

This is the new trendy crase amongst ladies these days in the waist training...it was  made popular by Kim. Ladies are now wearing corsets for hours at a time, some even to bed, to help compress their core, which is supposed to eventually shrink their waist and give them that hourglass figure (like Kim), but is it safe to wear it all the time and does it really work?? That's the big question.....