Wake Time Wins

Sleep scientist Matthew Walker put a hard number on the cost of cutting sleep: trimming from 8 hours to 6 does not save you 2 useful hours. It quietly drains a big slice of next-day thinking — slower attention, weaker memory, more fog.

The most useful fix is also the easiest: a fixed wake time beats a fixed bedtime. Get up at the same hour every day, weekends included, and your body clock settles within a couple of weeks. Sleeping in on Saturday gives you "social jet lag," so your body never learns when to wind up or wind down.