(JTA) – Dave Goldberg, the CEO of Survey Monkey and husband of Lean In author Sheryl Sandberg, died suddenly while on vacation, following a fall off a treadmill. Goldberg, 47, was at a resort in Mexico on Friday, May 1 with family and friends, The New York Times reported Monday. The cause of death was not immediately announced and was the subject of much media speculation. “Efforts to revive him at the gym and the hospital were unsuccessful,” a person close to the family who did not want to be identified told the Times. Goldberg and Sandberg, the chief operating officer of Facebook, were married in 2004 and have two children. Goldberg joined Survey Monkey, an online cloud-based company that helps organizations conduct surveys, in 2008. He previously worked at Capitol Records and founded a music company called Launch Media, which was bought by Yahoo in 2006. Sandberg has not publicly commented on her husband’s death.