Former Nottingham Forest midfielder Carlton Palmer says he suffered a suspected "small heart attack" on Sunday.
The 57-year-old was running the Sheffield Half marathon but said after experiencing problems early on he was admitted to hospital and kept in overnight for tests.
In 2016, Palmer required a life-saving five-hour operation for a heart condition.
He tweeted on Monday: "Thank you so much for all the lovely messages. I have being kept in hospital with a suspected small heart attack. They want to find out what has caused this problem so tests are ongoing. I will keep you updated."
Palmer played for clubs including West Brom, Leeds and Southampton during a career which spanned more than two decades.
He made 16 appearances for Forest in 1999 where he scored one goal before leaving to join Coventry City. He also made 18 appearances for England, scoring once.
READ NEXT
