A gradual decline in effectiveness may be easier to see in the work record than in memory. Preparation takes longer. Decisions are reopened. Work that once finished during the day moves into evenings.
No single sign identifies the cause. The pattern is a reason to investigate.
Compare like with like
Choose a recurring part of the role and examine how it has changed. Are the decisions more complex? Has the team lost experience? Is the executive carrying responsibilities that were previously distributed?
A comparison with an earlier period is useful only if those differences are considered. Otherwise, normal growth in complexity can be mistaken for personal decline.
Ask a trusted colleague for concrete observations. What now requires more follow-up? Which questions return repeatedly? Avoid asking for reassurance about whether you still seem sharp.
Test a plausible explanation
If the problem appears to be overload, remove or transfer a defined responsibility and observe the result. If information arrives late, change the preparation process. If authority is unclear, settle the decision rights.
Keep the experiment specific enough to learn from it. Changing the calendar, reporting structure and team at once may improve things without clarifying why.
Persistent changes in health, mood, memory or sleep deserve appropriate professional assessment. An operating review cannot determine a medical cause.
The useful outcome is a better explanation of the change and a working arrangement that addresses it. A dramatic story about hidden decline can be less helpful than a careful account of what became harder and when.
