Sublime

For King Henry, the relevant distinction is not simply between sleep and wakefulness, but between a perceptual vigilance sustained throughout “the all-watched night” and the sound slumber and “vacant mind” of the yeomen or peasant.

neither naps nor caffeine can salvage more complex functions of the brain, including learning, memory, emotional stability, complex reasoning, or decision-making.

In fact, walking is particularly good for the brain.

A couple of key scientific findings point the way. The first is that sleep is more important than food. You can go a week without eating and the only thing you’ll lose is weight. Give up sleep for even a couple of days and you’ll become completely dysfunctional.

without sleep, our brain reverts to a primitive pattern of uncontrolled reactivity. We produce unmetered, inappropriate emotional reactions, and are unable to place events into a broader or considered context.

Sleep six hours or less and you are shortchanging the brain of a learning restoration benefit that is normally performed by sleep spindles.

Ten days of six hours of sleep a night was all it took to become as impaired in performance as going without sleep for twenty-four hours straight.