A time traveler like Hiro would have two major problems, for one, when someone stops time they continue to age while the rest of the world doesnt, so they are older then they are supposed to be at that time and will get age-induced illnesses and death much sooner then they should.
Also, along the same lines, if he goes back in time he will be(obvioulsy) older then the world at that time, but thats not the problem. The issue is when he returns, if he returns to the same time he left he will be older there to because he lived some in the past and returned so little or no time has elapsed since he had left so he is older, this alos is true with going into the future , but he will only be younger instaed of older.
So, he will live the same amount of time through his own eyes, but to everyone else it will seem as though he is older or younger then he should.
There are solutions, such as, if you whent to the past for two days, return two days from when you left originally. Or, if you stayed in a time-frozen world for 30 min. when you are done go 30 min. into the future...



just some thoughts

This made me think of that Simpsons Halloween episode where they stopped time for 15 years or whatever and when the other people in Springfield went back to normal Bart and Milhouse were suddenly a lot older.

Yeah, he just has to skip however much time he lost..

or maybe he just won't have that aging problem at all. you never know.

It seems to me that whenever Hiro is gone for an extended period of time, he skips ahead that same amount of time when he returns to the present.

I have another question about time travelers, if one time traveler stops in say, Germany, wouldn't that stop time for those in NY? And if that happened wouldn't all time travelers have to deal with time being stopped a lot by all the time travelers in the world? If I were Peter I'd get pretty fed up if I had to wait for Hiro to unfreeze time again before I could continue interacting with someone else.

Actually the time traveler does not stop time. He steps out of time. Then he can choose to stay where he is in time or move forward or back. That is the simplest explanation I can give you. It gets really complicated.

I wondered about that too. I assumed that unless Peter is in close proximity to Hiro, he freezes in time unaware just like everyone else. It's only when they're in the same room that they are free from each other's ability.