Sweating with the Oldies...

They say (whomever "they" are) that 50 is the new 40.  This is all well and good, but it still doesn't help the fact at 42 my knees make more noise than the brakes on my car, I haven't been able to visually locate certain parts of my anatomy in several years, my digestive system doesn't like being in the horizontal position, and the heaviest thing I lift on a typical day is a coffee cup.

How does one of such spectacularly deficient physic prepare for a hike that is roughly 10 times more strenuous than ones normal daily routine without blowing out a knee or having a coronary?