you gotta admit however that Bernie just doesn't have that presidential "look"....its very hard to picture him as president...especially with that shrill and hoarse voice of his...he sounds like an 80 year old woman who has smoked all her life 
He looks like a grandpa, and that's what he is. My only concern with him is that he wouldn't be nearly cautious enough against those out to stop him.
And right now he's exhausting himself with the campaign, so he's about as physically-extended as it gets. It would be tough on anyone, especially an older person.
But I'd bet he's in better shape than Hillary. I'm thinking she may smoke and that she's managed to keep it from the public.