Sleep Is the Workout

Build for Health with Srdjan Injac · Oct 1, 2026 · 30m

You can do everything right in the gym and still undo it on the couch at midnight. Lifting doesn't build muscle while you're lifting. It damages muscle and sends a signal. The rebuilding comes later, mostly while you're asleep, and it depends on conditions that a short night takes away.

This episode goes inside that night shift. Deep sleep brings a major pulse of growth hormone, but calling it "the muscle-building hormone" sells short what it's actually doing. Testosterone and the nervous system have their own overnight jobs, and strength turns out to be partly something your brain has to…