Who isn't? It's a big concern since both major party candidates are senior citizens. Yes Trump appears to be in much better health than Clinton appears to be. I said appears to be. Looking at VPs, the Trump camp wins out big time, in my opinion.
Whether through health, ongoing/new investigations, guilt by association, I would imagine a short lived (no pun) presidency. Hillary is just praying to run out the clock before wiki further raises questions.