Join Date: May 2007
Location: Boston (sort of)
Bikes: 1 road, 1 Urban Assault Vehicle
If cycling is your only form of exercise, then mileage per week may be a pretty good metric of how well you're doing, although you do have to factor in some recovery from a major event. OTOH, how fast you can bounce back from a century is a valuable metric too. The bottom line is that if you're really feeling fatigue, that would suggest that you're either overdoing the exercise, or underdoing something else. Only you know the answer.