Sleep science

If you wake up at 3 a.m. and suddenly feel wide awake, your first instinct might be to panic. Modern sleep culture has convinced many people that healthy rest must happen in one uninterrupted eight-hour stretch, so waking in the middle of the night often feels like a sign that something is wrong. But history …

For most of human history, night was a period of natural darkness. The sun sank below the horizon, the stars emerged in a velvet sky, and the body followed an ancient script that had been written into our biology over millions of years. Today, however, very few of us ever experience a truly dark night. …