What do you do?
Training the body to deal with hypoxia is very difficult. The real key for flatlanders and shoremen is to never compare yourself with someone who lives at altitude.
Train to be in the best cardio health possible, drop as many pounds as possible.
Take time to acclimate at altitude, and drink lots of cocoa.
63 years living at sea level. Quick step hiking 4-5 times a week, 5-6 miles with weighted pack, of 25 lbs. Did a Wyoming Elk hunt last year at up to 10,000ft+. Just about the time our 6 day hunt was finished, we were almost fully acclimated. Don't think there is a substitute for time spent at higher altitudes? We try to get in a few days before our hunt begins and keep up the same training routine as done at home.What do you do?