because then they're at sea level. this is a life-threatening situation. it's what mountain climbers get when they get to these areas and are acclimated to it. you can imagine, an 86-year-old landing in there and over the next day or two getting this type of condition. >> you talk about his age, doctor. buzz aldrin has been to the moon and back, right? the south pole at least is on this planet for him but he is 86. are there any warnings you would give to someone considering a huge trip like this, of that age specifically? is it just a matter of overall physical fitness and health? >> it's interesting with high altitude pulmonary edema. it doesn't affect people older as younger people. we're not quite sure that happens. you want to make sure you're in the best physical health you can be because it's an extremely harsh environment, extimely isolated environment. it's a long flight to get there. main thing i would say, talk to your doctor, make sure have you what you need lined up and make sure you're in good condition to go there. >> dr. john torres, thank you very much.