Sarah

“If you’re not sleeping well, your body interprets that as an emergency,” Roxanne said. “You can deprive yourself of sleep and live. We could never raise children if we couldn’t drop down on our sleep, right? We’d never survive hurricanes. You can do that—but it comes at a cost. The cost is [that] your body shifts into the sympathetic nervous system zone—so your body is like, ‘Uh-oh, you’re depriving yourself of sleep, must be an emergency, so I’m going to make all these physiological changes to prepare yourself for that emergency. Raise your blood pressure. I’m going to make you want more fast food, I’m going to make you want more sugar for quick energy. I’m going to make your heart-rate [rise].’…So it’s like all this shifts, to say—I’m ready.” Your body doesn’t know why it’s staying awake. “Your brain doesn’t know you’re sleep-deprived because you’re goofing off and watching Schitt’s Creek, right? It doesn’t know why you’re not sleeping—but the net effect is a physiological sort of alarm bell.” In”
― Johann Hari, Stolen Focus: Why You Can't Pay Attention—and How to Think Deeply Again