We don't know how to do that yet. It would be nice to be able to knock people out somehow, like hibernating bears, and travel to the stars packed like popsicles, but our understanding of how to get the human body to do this is, so far as I have ever heard, not there yet. Nor does it seem that it is within grasp in the near future. There are many animals that can hibernate for months and years, perhaps we will eventually find out how to put humans in such a state, and prevent the aging process too. It sounds like a tall order to me, but it is our only option for interstellar travel, and possibly even travel inside our own solar system.