Fox, however, is OK.
"I am doing fine," Fox told NFL Media columnist Michael Silver in a text message. "Don't believe everything you hear in the press! We are just running some tests and will know more in a few hours."
Below is the official statement from the Broncos:
"Denver Broncos head coach John Fox was taken to a Charlotte-area hospital after feeling light-headed while playing golf on Saturday. He is being held at the hospital for testing and further observation. Our medical staff is currently in contact with coach Fox, his family and the doctors who are treating him. Additional information will be provided as it becomes available."
NFL Media's Albert Breer reports that it's been determined Fox didn't have a heart attack, per a team spokesman. The Broncos later tweeted that Fox will be held overnight at the hospital for observation.
The Broncos are on a bye week.