Oh, oh sounds like someone has been hitting it too hard... (CNN) -- Billy Joel's daughter with Christie Brinkley fainted on a New York cabaret stage Saturday, her rep said Monday. An emergency room doctor concluded that Alexa Ray Joel, 28, experienced vasovagal syncope, a common cause of fainting that "is usually harmless and requires no treatment," Joel rep Claire Mercuri said. In vasovagal syncope, according to the Mayo Clinic website, a sudden drop in heart rate and blood pressure can cause reduced blood flow to the brain, which results in a brief loss of consciousness. Joel was performing to a sold-out crowd at The CafÃ© Carlyle on Manhattan's Upper East Side when she collapsed and was rushed to the emergency room at New York Presbyterian Hospital, Mercuri said. "Ms. Joel was taken ill earlier in the afternoon and announced from stage that she pulled out her back and neck, but wanted the show to go on," she said. It was closing night of her two-week run at the venue.