I like to think of sleep as the essential “backstage” human function. The audience is paying attention to what’s going on on-stage – sword fights, great romantic gestures – but backstage is where the real drama takes place as sets, props, costumes are assembled for the next scene. Ditto sleep. While we’re lights out, the brain, our stage manager, juggles the hormonal and metabolic machinery responsible for cellular cleaning, repair, rebuilding. That’s what’s required for the show to go on the next morning and, we hope, for many decades to come. Call it aging well. When sleep goes off the rails – I’m not talking about the occasional bad night but an entrenched pattern of insufficient or fragmented sleep – it throws off the balance of all those moving parts –and rapid aging kicks into high gear.