Fig. 3.

The spectrum of intrinsic capacity from the perspectives of organ and systemic level, and their clinical manifestations. In the first stages, there are changes in isolated organs that can still be reversed and do not impact function due to a high functional reserve. As the condition progresses, other organs start to deteriorate, due to the aging processes or to the accumulation of chronic diseases sharing similar mechanisms of damage. At this stage frailty status appears: there is still enough functional reserve to maintain functional autonomy, although some deterioration in performance-based tasks can be observed if carefully assessed. If the condition continues progressing, functional reserve is depleted and disability takes hold, with few chances for recovery.