By anticipating (scheduling) a 20 min break, I am able to sustain 90 min time blocks to get my tasks complete.
My preferred workflow is four 90-min blocks each day:
6:00 AM - 7:30 AM
Recess 1
8:00 AM - 9:30 AM
Recess 2
10:00 AM - 12:30 PM
Recess 3
1:00 PM - 2:30 PM
Recess 4
3:00 PM - 4:30 PM
Meditate / Exercise
You'll notice a 30-min 'recess' break between blocks (which are actually 20 min breaks + a buffer). This ties back to the recess we had in grade school. In order to sustain five solid productive blocks/day (working towards 3), I force myself to take a break to:
Ideally, I am working in plan out my next 90 mins during recess.
I'm also working to apply the lessons of effortless and winning the week.