There is no moment of failure. No identifiable turning point. No event the executive can point to and say: before this, I was performing at my ceiling; after this, I was not. The decline is too gradual for that kind of narrative. It accumulates in increments so small that neither the executive nor the people around them can locate the change as it is happening. The comparison that eventually makes it visible is not to last week but to two or three years ago — and even then, it is visible primarily in the output, not in the experience.

This is the slow leak: the progressive narrowing of executive performance that happens beneath the threshold of detection, over the timeframe of years rather than quarters, through the accumulation of physiological costs that individually are unremarkable and collectively are consequential. Understanding its mechanism is the starting point for addressing it — because the slow leak does not respond to the interventions designed for acute performance problems.

The Accumulation Mechanism