From what I remembered Sam was nearing 60 in Chaos Theory, and at least the creators wanted to convey the feeling that Sam was really old now (him grunting for everything, even for pipe climbing).
He's like in his late 40's or early 50's now. Which is very old in real life terms, but it isn't the same as the old guy who had funny conversations with Grim about lasers being so 80's ("90's?") or him doing NAVY SEALS operations while Grim was still in Highschool ("yuck")









