Purpose: To analyze best 1-h unaccompanied performances of master athletes in ages ranging from 35 to 105 y to estimate the decay of maximal aerobic power (MAP) across the spectrum of age. Methods: MAP at the various ages was estimated by computing the metabolic power (${\dot{E}}_c$) maintained to cover the distances during best 1-h unaccompanied performances established by master athletes of different classes of age and by assuming that they were able to maintain an ${\dot{E}}_c$ equal to 88% of their MAP during 1 h of exhaustive exercise. Results: MAP started monotonically decreasing at 47 y of age. Thereafter, it showed an average rate of decrease of ∼14% for the decades up to 105 y of age, similar to other classes of master athletes. Conclusions: The results confirm, by extending the analysis to centennial subjects, that MAP seems to start declining from the middle of the 5th decade of age, with an average percentage decay that is faster than that traditionally reported, even when one maintains a very active lifestyle. The proposed approach may be applied to other types of human locomotion for which the relationship between speed and $\dot{E}$ is known.