How long can you sit and work with full efficiency?
Personally, I can’t stay in my seat without feeling restless for more than an hour.
Research (plus many people’s experience) has observed that people are the most effective at whatever they’re doing, from hitting home runs to writing computer code, when we access a special state of deep concentration.
This phenomenon is often called the “zone.” It’s like being in a flow where you stay focused without any effort, everything comes easy and there’s a special energy in everything you do. You’re engaged and enthusiastic about the task you have at hand.