How would Batman get enough rest?
The difficulty for Batman is he's going to be trying to sleep during the day. He's going to be really tired, actually, unless he can shift himself over to just being up at night. If he were just a nocturnal guy, he would actually be a lot healthier and have a lot better sleep than if he were doing what he does now, which is getting some light here and there. That's going to mess up his sleep patterns and duration of sleep.
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How would all those beat-downs have affected his longevity?
Keeping in mind that being Batman means never losing: If you look at consecutive events where professional fighters have to defend their titles—Muhammad Ali, George Foreman, Ultimate Fighters—the longest period you're going to find is about two to three years. That dovetails nicely with the average career for NFL running backs. It's about three years. (That's the statistic I got from the NFL Players Association Web site.) The point is, it's not very long. It's really hard to become Batman in the first place, and it's hard to maintain it when you get there.
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How many of us do you think could become a Batman?
If you found the percentage of billionaires and multiply that by the percentage of people who become Olympic decathletes, you could probably get a close estimate. The really important thing is just how much a human being really can do. There's such a huge range of performance and ability you can tap into.