A recommendation for tourists traveling to Peru to avoid the effects of altitude sickness is to spend time at lower altitude (such as Arequipa 7,000 ft - second largest city in Peru) prior to visiting Cusco or Lake Titicaca at 11-12,500 ft. For ordinary people who wish to climb Mt. Kilimanjaro (19,340 ft), there are several treks that progress up the mountain in stages for the sole purpose of allowing the individual to acclimatize to the increasing altitude.
Last year on the week of the PPA, I went to the top of PP and did some training above timberline. This was during the taper period, but assuming that some acclimatization can take place in only a few days, it seemed a reasonable thing to do. The intent was to send a message to my body that I was in thin air and that some adjustments were necessary, at the same time keeping in mind that this is during the taper just before the race.
When I looked at the results, I noticed that I had one of the faster times from A-frame to the top for people around my finish time. HOWEVER, I purposely started out slow so that had probably a bigger effect than the brief amount of training at high altitude.
I live at 8,000 ft and I have noticed that when I spend time at sea level and return home that I have lost some acclimatization. From my perspective, the acclimatization to high altitude disappears fairly quickly so high altitude training should probably be done close to the time of the upcoming race.
For flatlanders, this may be an interesting link.