Cech has been in good form this season and hope to make it three league clean sheets in a row when the Gunners host Huddersfield on Wednesday.
“He gets older, we all do that, but I think he is fitter than ever,” Wenger said. “He puts a lot of attention into the preparation. He is slimmer than before. I think he benefits from that.
“He has lost some weight. Not too much, two, three kilos only. But it’s a lot if you want to make a horse lose a race, you put a jockey with one or two kilos more on the back, and the horse is quite big.
“He looks after his whole lifestyle because he feels better and because he wants to be the best. Petr Cech is a perfectionist. And you don’t make a career he has made if you have not that obsession, always to be at your best.
“I remember Edwin Van der Sar at Manchester United, I compare them. They are intelligent, they have great similar size, similar quality. And Van der Sar stopped at the end because he decided to stop.
“Because Manchester United wanted him to stay one more year longer. I don’t rule out [Cech playing until he is 40], but that will only be down to the performances,” Wenger said.