How Do You Survive When You Travel?

Sam's body is still in a lab somewhere unconscious, probably hooked up to IVs and monitored by doctors. As far as we know, yes, but my body comes with me. That's why I had to sleep, and he didn't. He said he never gets tired or hungry. And that's why he was wearing old clothes, air clothes. It's what the other time travelers used to do when they would go on trips. Part of the mental deal, I guess. But how have you survived? Some of your trips have been far longer than a human should go without food or water.