In Passengers, why didn't Jim's hair and beard growing? Even after we die, beards and nails are supposed to grow?
I do not have much idea about hibernation, but according to this article, after death the hair and bear does not grow.
It just looks like it has grown, but actually it is our skin that is disappearing by drying that reveals more of the nails, which in turn makes it look longer.
I suppose hibernation must be doing the same thing since you do not consume any food or water.
Hair is made of a protein called keratin and dead cells.
For hair to grow, your body needs to be processing some energy to make it grow.
If the technology to put people in hibernation would exist, then this would like be in a way that stops or severely slows down the body's metabolism (energy processing).
If the metabolism isn't stopped (and since we are in hibernation we can't eat to replenish the energy), we would use up all energy in our body during the hibernation and die. Because of this, it is to expected that our hair wouldn't (significantly) grow during hibernation.
Now it is a common misconception that our hair and fingernails grow after death.
This is not true. Instead a persons fingernails and hair may appear longer because the skin around them has retracted.
This is due to dehydration that causes the skin and other soft tissues to shrink.