high altitude illnesses

The World Marathon Challenge of 7 marathons on 7 continents in 7 days is about to get underway. Are such extreme endurance sports healthy? Worth the risks?
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.