@Reimon, didn't you saw Mebius? It is said that aging is slower in space.
Yeah. Besides, like what you have added, Ultramen are different beings.Are you talking about what happened to GUYS Captain Shingo Sakomizu? That his aging was slowed due to traveling near light-speed (ie, time dialation)?
And, Ultras are very long-lived beings, living for thousands of years.