I spent a decade in the dark, sitting in dim clinical rooms while patients lay wired to a headbox, their brains humming with electrical activity. I’ve seen the raw data—the actual, jagged reality of what happens when we drift off—and it looks nothing like the polished, colorful graphs your smartphone presents to you. Most people are obsessed with chasing a perfect “score,” but if you want to understand how sleep cycles work, you need to stop looking at your wrist and start looking at the architecture of your brain. Your wearable might tell you that you had a “great night,”…

I spent ten years in the dark, hunched over a monitor in a quiet clinic, watching the jagged lines of brainwaves dance across a screen while my patients slept, wired to a headbox. I’ve seen the panic in a person’s eyes when they realize their “perfect” sleep score from a $300 wearable doesn’t match the reality of their exhaustion. The truth is, your wristband has no idea how sleep is structured through the night; it’s merely guessing based on how much you toss and turn. It can’t see the delicate, invisible shifts between deep restorative stages and the chaotic, dream-filled…