To technical founders who code, how do you manage writing code for 12-14 hours per day?

In a few weeks I'm leaving my employed life for good to start working on the MVP of a side business I've been growing for almost a year.I will do all of the programming in the beginning. I'm prepared to go into this full steam. But I realize it's not realistic to think I can do programming for 12-14 hours per day without going nuts or writing shit code.So what is a good strategy for coding the whole day?My own idea: Coding in 2-4 hour sprints.I love meditation. It calms me. Resets my mind. So I thought I would code in 2-4 hour "sprints" where I:Turn off my cell phone and notifications on the computer.Code uninterrupted for 2-4 hours until I get a natural break (e.g. when a new module/component is finished)Take a small break from the computer, 15-30 minDo some meditation, or light house chores, or go out for a walk. Anything that's not mentally demanding.Get back to coding again.But I'm most curious to hear from you who are already doing this, how do you manage it? see hubwealthy.com/wealthy