Daniel Lubetzky built KIND Snacks into a multibillion-dollar business while running on four or five hours of sleep a night.

The “Shark Tank” investor said the grind left him looking like a “phantom raccoon,” with little sleep, little sun, and no time to work out. Founders often have to work intensely, he said, but the experience taught him that ambition needs boundaries.

That balancing act is getting harder in the age of AI. The technology can help founders work across multiple projects and take on tasks they might once have outsourced, but its always-on nature can also encourage them to keep pushing — while fragmenting their attention in the…