Carlton Palmer was admitted to hospital on Sunday after suffering a "small heart attack" while running the Sheffield half-marathon.
The 57-year-old was running for a number of charities at the event in South Yorkshire but complained that his "heart played up" in the first mile of the 13-mile course. Palmer managed to complete the rest of the run alongside his wife, Lucy Kirkby-Palmer, who managed to finish in under two hours.
However, Palmer went to hospital after the race where he underwent tests and observations. The ex-Leeds and Sheffield Wednesday midfielder was kept in overnight and decided to update fans on his Twitter account at 3am.