What I meant was "what sustained acceleration could humans tolerate? Others have answered that question, and also provided the surprising (to me, at least) bit

What I meant was "what sustained acceleration could humans tolerate? Others have answered that question, and also provided the surprising (to me, at least) bit of data that a 1G constant acceleration -- currently not remotely possible -- would put the entire solar system within easy reach. And yes, I understand about gravity assists and the like.