Backpack Travel

I watched a special the other night, about people who give up their jobs & lives, to travel the world alone for a few months or even years. This particular special followed a guy who quit his high paying job, packed his backpack & headed out for a year of travel. I wonder if he had any travel medical insurance? I mean, you would think that would be a brilliant idea. Especially with traveling to some under developed countries & staying in not so clean places. I know that I love to travel, but there is no way I would just up & travel the world alone with my backpack.