So i know that elapsed time might be different between two events measured by observers on different distances from gravitating mass.

But for example in movie interstellar father went to space, and since planet was near black hole 1 hour spent on that planet was 7 years on earth. this cause father to remain at age 40 or so and daugher go from like 20 to 70 in the time passed.

my question is, isnt 1 year passed on earth 1 year passed on that planet. how is it, that human body (cells) didn't age ? shouldn't they age normal and father would die before the daughter, no matter time passed ?

i know movie is fiction, but people say astrounats age slower when on iss for few microseconds or something. so is the concept of movie correct, and if so how is it possible that gravitational pull affects aging of human cells ?