I don’t think the stresses of the Presidency impact those who are capable. They’re used to crisis management, and don’t doubt themselves because they’re used to doing the right thing. Case in point, Ronald Reagan.
Reagan aged too...he just colored his hair...like Sarah does
Reagan was good at delegating
too much on occasion
Reagan, Jefferson, TR (for better or for worse), Ford, Truman, and even George W. left the office with more or less their same energy level they had when they entered.
It will age you for sure, but if one is ready for it, the aging will be slight and not debilitating.
Everyone ages; some people age worse than others, due to stress, genetics, and/or health problems or lack thereof.
It is only lately, in the history of mankind, that people refuse to accept the natural aging process and have BOTOX shots, plastic surgery, etc. !
Time once was that men who had extremely young girlfriends/mistresses/wives were applauded. WHY? Because of breeding.
Now, some women take on "boy-toys". It has actually become more or less accepted. WHY ? It has nothing to do with "breeding" !
Don't we all take umbrage when people say that Palin is "too pretty" and/or compare her to a Barbie doll? So what if she ages badly, throughout her presidency and who is to say that she will?