The Manchester United manager was rushed to hospital after suffering a nose bleed during a function in Glasgow two months ago.
Ferguson looked fine on the club's trip to South Africa and confirmed there was no problem with his heart, but conceded he had been pushing himself too hard, saying: "I took too many flights that week. It was a bit silly to be flying as much as I did. Belfast, Berlin, Newcastle, Manchester, Belfast, Manchester, up to Glasgow. It was seven flights in five days."
He went on: "If you do a straight 12-hour flight to South Africa and back there wouldn't have been the same problem. But I was going up and down all the time.
"It's not as if it was anything to do with my heart but when the club doctor explained what he thought it seemed reasonable.
"We are all vulnerable to age aren't we? It doesn't come without penalties.
"Maybe that was a way of telling me to slow down a bit in terms of travelling."
It will be interesting to see how Ferguson handles to massive demands being placed on him over the coming months as he looks to rip the Premier League title back from Manchester City.
"People may say Manchester City are the team to beat but I don't agree," said Ferguson.
"We are the team to beat because of the way we react and the way we have bounced back from losing the league in the past. We will be strong this season."