"I feel great," the Real Madrid midfielder told a news conference in Madrid on Thursday. "Over the last month or two months my fitness has been the best it's been for a long, long time, better than at any time since I was at Manchester United.
After a subdued start to the season, Beckham has been playing some of his best football in recent games.
He played an instrumental role in Real's 4-2 victory over arch-rivals Barcelona earlier this month and was the man of the match in his side's 2-1 comeback victory over Villarreal last Saturday.
Beckham attributed his improvement to the new fitness regime introduced by Vanderlei Luxemburgo when he took over as Real coach at the end of last year.
"At Manchester United it was much more physical each game than here in Spain. So during the week you worked much, much harder," he said.
But since Luxemburgo arrived, he has worked us very, very hard which is good for me and for the team. I'm happy about that and that's a big part of why my fitness levels are much better."
POSTIVE INFLUENCE
Beckham also reiterated his desire to see out the remaining two years of his contract at Real
"I want to stay here at Real until I finish playing football. I've played for one of the biggest clubs in the world in Manchester United, I've captained my country and played for another of the biggest clubs in the world in Real Madrid.
"It would be a great way to finish my career having done all that."
Beckham has not won a trophy since joining Real from United at the start of last season and readily admitted his team faced an uphill task in trying to deprive Barcelona of the league title this time round.
"It's very important for Madrid to win every game," he said. "I suppose anything is possible, but if Barcelona keep winning then there is nothing we can do. Barcelona are playing some very good football."
Beckham stressed that despite the fact that he is now one of the oldest members of the England squad he still felt he had a lot to offer the national side.
"I've got a lot of experience and that's what I can bring to the England team. I'm England captain and that's one of the biggest honours for me. I can add that experience to the team as well as my hard work and ability.
"Although I'm turning 30 I still feel as though I've got quite a few years left in these legs to carry on running around on the football pitch."