Denis | Secrets of life on Instagram: "1. The break was not “rest” — it was a second cognitive phase. In medieval court records, judges mention people writing contracts and wills “after first sleep.” A sleep historian told me: “The clearest thinking happened between sleeps.” During this window, cortisol is low, dopamine stable, and the brain stops defending identity. That’s why complex decisions were postponed to the night break. 2. Deep sleep quality improves, not worsens. Polysomnography data