Physical Preparation to Ascend Above 5000 Meters

I've been doing quite a bit of reading on the topic of the effects of high-altitude on brain and body.  Data collection for this type of research generally takes one of three contexts: (1) in a hypobaric chamber where the air pressure is artificially reduced, (2) on a mountain during an ascent, and (3) at a 'base' air pressure in a 'before' vs. 'after' comparison.  Each context has its advantages and disadvantages.  What this research tells us is what happens on average.  And many of us like to think of ourselves as "better than average".  Take a minute to decided if this is actually the case and if we might consider following recommendations derived from average people.

I assume that each person ascends Kilimanjaro with the expectation that their brain and body will continue to function as it did before they started.  I think this is the expectation for any extreme sport-- that we won't become permanently injured. I have had my share of injuries and fortunately I think I've fully recovered from most of them.  What is common to all extreme sports is the inherent risk of injury; those of us who undertake these activities accept risk as our way of life. What is clear from the research I have read is that we will encounter a significant reduction in the oxygen available to our brains and bodies.  While this is well-known, it is not well-known how each of us individually will be affected by the reduction in oxygen and and air pressure and how each of us will 'bounce-back' from oxygen deprivation.  The research is clear that above 5000 meters (5000 is a nice round number), for those of us essentially starting at sea-level, on average the risk increases.  That said, their are many individual variables to account for that have an impact on the calculation of one's own individual risk such as the duration of time above 5000 meters, the physical preparation beforehand, our own genetic dispositions, and so on.  The list is long.  It would be extremely valuable to have a little machine in our pockets that could tell us our individual likelihood of returning home with an injury. One day such a device might exist.

The human body is an amazing machine that ultimately gets stronger when you work it, within reason.  When a buddy and I rode our bicycles 7600 km in 57 days to cross Canada in its entirety, various bike parts wore out but our feet, legs, and knees got stronger.  With the goal of completing this challenge and coming out stronger than we were, we must strive to be at our physical best before making the ascent and we must be wise in our activities on the mountain.  "Pole, pole", they say.