Yeah, I've done it quite a lot. It's really quite simple. Go to your local international airport, buy a ticket, board the plane, have a few complimentary drinks, and once the plane gets to cruising altitude, you've effectively acclimatized to 8,000 meters.
Shouldn't take more than an hour or two once you take off!
Actually, "At a 39,000 foot cruise altitude, the cabin pressure is equivalent to 6,900 feet or pressure of 11.5 psi (about) 450 feet less than Mexico City. reference here