I find myself in a similar situation. At the age of 72, I'm in what would probably be considered quite good physical condition. The fly in the ointment is that I will never be 17 again. What this ultimately means is that even physically fit for my age, I do not recover nearly as well and as quickly as, say, a lad of 50. This means that I must pay very careful attention to recovery nutrition. In our present age, quite a bit is known about this issue. I thought I was being careful the summer of '10 but, evidently, not careful enough. I reached a point toward autumn where I lost motivation to ride and my body felt tired even after numerous days of rest. My reading on training has revealed that a large part of the solution, a much larger part of the solution than originally thought, is based on proper recovery nutition. Read up on this issue and pay careful attention.