Most people can only sustain deep focus for around 50–60 minutes.
Research by Gloria Mark, a professor who has spent over 20 years studying attention and fatigue in real workplaces, shows that sustained attention drops sharply after about an hour. Error rates increase, decision quality falls, and emotional regulation weakens, often before we notice it.
Research into elite performance by Anders Ericsson, the world authority on how experts sustain performance, found that high performers do not work longer hours. They work in focused blocks with deliberate recovery built in.
This matters for leaders.
Because when they are scheduled back-to-back all day, the issue is not time. It is cognitive overload.
And this is where assistants can step up and protect performance.
Here are 10 ways assistants can protect executive time and thinking.
1. Stop back-to-back scheduling after high-stakes meetings.
2. Build 15-20 minute buffers after meetings longer than an hour.
3. Protect thinking time as firmly as external meetings.
4. Group similar meetings to reduce context switching.
5. Challenge “just 15 minutes” meetings that fracture focus.
6. Schedule complex decisions earlier in the day.
7. Schedule white space so thinking and preparation can actually happen.
8. Avoid stacking people-intensive meetings without recovery.
9. Frame breaks as preparation, not downtime.
10. Push back calmly and consistently when calendars become unsustainable.
This is not about being nice. It is about protecting judgement, clarity, and leadership quality.
If you manage a calendar, you manage energy. And energy management is leadership support at its highest level.
And one final reminder: if you are building recovery into your executive’s day, make sure you are doing the same for yourself. You are human too.
Save this if you manage calendars.
