Stallone, 66 and Schwarzenegger, 64, who paired in "The Expendables 2", have enjoyed long careers on big screen in big budget action films, reported Contactmusic.
"It comes at a price. Arnie must have lifted a million pounds of weights in his life but it comes at a price. There's only so far you can push the machine, then it's a case of taking it to the mechanic to get this part fixed or that part fixed. These days that happens more and more," he said.
Stallone said he would slow down now as he is getting older.
"I still love the challenge. I get there and I go, 'Let me jump off, let me go into the water.
"I don't know how people do that green-screen work. I've done a bit and it drives me crazy. I like the heat of an explosion in my face, a hunk of tin flying past my head 30ft from where it should have gone. It's hard to get the emotion without it. I'm very proud of this movie because 90 per cent of the stunts are in camera," he added.
