I don’t think Bernie is worried about dying in office. I trust that Bernie will pick a good VP to carry the torch with his departure, if he should win.
It’s also worth noting that Bernie spent a good deal of his time in his youth running for exercise and sport. I believe that his willingness to exercise when he was young has provide him with endurance in his old age.
Besides, Orrin Hatch was in his 80’s when he retired, and he’s among a rather large group of octogenarians in Congress, who served in their 80s, some in their 90s. Nobody complained about that before, and now it’s a problem?
And then there’s Jimmy Carter who still builds houses in his 90s, and he’s still coherent.
Yes, Bernie is a crusty old fart. I get that. I just want him in the White House for his policies, not his age.