Kyle Brennan, 41, wakes at 4:47 a.m. in a studio apartment in Austin. His morning routine takes 2 hours and 14 minutes. He has not seen his children in eight months.

"I was tracking everything," Brennan said, gesturing toward a whiteboard covered in hand-drawn graphs. "Sleep latency, HRV, glucose response, ketone levels. But my numbers kept crashing around 4 p.m., and I couldn't figure out why."

The culprit, he discovered, was screen time—specifically, the 47 minutes per day he spent negotiating iPad access with his son and daughter, ages 7 and 9.

"It was a false binary," Brennan explained. "Either I win the screen time battle and destroy my cortisol, or I lose and they get unlimited dopamine poisoning. There's no third option."

There was, he realized, a third option.

Brennan's ex-wife, who declined to be interviewed, was awarded full custody in September. Brennan describes the arrangement as "a co-parenting pivot" and "the single biggest optimization of my protocol stack."

His screen time metrics now hover at zero. He cold-plunges at 5:15 a.m. without interruption. His glucose remains stable through dinner, which he eats alone at 5:30 p.m. before a 12-hour fast.

"I saw this TED talk once about how constraints breed creativity," he said. "Kids are a constraint. I just removed the constraint."

Brennan now spends his former negotiation hours on "deep work"—a term he uses to describe journaling, breathwork, and updating a spreadsheet that tracks his own optimization metrics. He posts his protocols to a Substack with 23 subscribers, mostly other men in the Austin biohacking scene.

When asked if he misses his children, Brennan paused for 4 seconds—he timed it on his Oura ring—before answering.

"I miss the version of them that didn't need a screen," he said. "But that version doesn't exist. The variables were uncontrollable. I'm not equipped to optimize someone else's dopamine."

He showed me to the door at exactly 7:15 a.m., when his "input window" opens.

"I'm happier," he said. "My numbers prove it."