At age 86, living legend Dr. Buzz Aldrin was recently medically evacuated from the South Pole. In the first of a two-part series, Dr. Jamie Wells shares an experience she had at high elevation with the former astronaut when addressing altitude illnesses, prevention and treatment.  
A drop in T-cell production may mean that astronauts are at least temporarily immunocompromised by space flight. To those of you who are eager for a trip to Mars, add "immunosuppression" to your list of concerns.
After nearly a year in space, astronaut Scott Kelly was nearly 1 1/2 inch taller when he returned to Earth. But that's far from the only change that the human body is likely to undergo when it spends time in microgravity.