Ultradian Rhythms: The brain focuses best in 90-minute cycles, but 50 minutes is the sweet spot for sustained intensity without burnout.

Set a timer for 50 minutes. Phone in another room. No email. When the timer hits, you must stand up and move for 10 minutes.

Try one block: Do your next major task using the 50/10 method. You will accomplish more in that hour than you usually do in three.