The only thing that relates age to getting tired is fatigue, which affects players agreed 27 and above. But I don't think it's related to pace (and also rest frequency). Seems to me like it just randomly hits every player who has played 35 minutes and above by the 42nd minute. I previously thought it only hit players who played above 40 minutes but tonight's game kinda proved it wrong.
That said, as mentioned by other users, your tactics will only affect the stamina of your own players.