The 31-year-old committed his future to the club by signing a fresh two-year extension last week.
"I think it's hard to plan ahead," the Fulham Chronicle quotes Hangeland as saying. "It may well be [my last club] but at the moment I'm feeling as good as ever, I don't miss games and feel fit, so who knows? I will take it a season at a time.
"We're being looked after so well these days. Our medical staff are fantastic and I think it's possible to carry on longer than it was five or six years ago, so I'll see how long I can go on for."
Hangeland is close to making 250 appearances for the Premier League outfit.