Sleep Is Where You Get Rebuilt

Drive a highway late at night and now and then you’ll come up on a closed lane. Orange cones, bright lights, a crew at work on the road. They work at night for a simple reason. That’s when the cars stop. You can’t fix a road while everyone is on it.

You’re built the same way, and I want you to take that to heart.

Start with rule one. You’re a whirlpool, and all day long the cars run through you. Food, work, talk, worry, light, noise. Sleep is when the lanes close and the crew comes out. In one study, the gaps between brain cells in mice opened up by about sixty percent while they slept. The waste of the day washed out much faster than when the mice were awake. Your body does other night work, too. In another study, people agreed to have a cold virus dripped into their noses. The ones who had been getting less than six hours of sleep a night were far more likely to get sick than the ones getting more than seven.

So sleep isn’t time off from your life. It’s the shift when you get put back together.

Now rule two, and this is the part that scares me a little. You can’t feel your own sleep debt. Your map of how short on sleep you are is one of the worst maps you own.

In one study, healthy young adults lived in a lab for two weeks. Some got eight hours in bed a night, some six, and some four. The ones who slept less got worse at simple tests of attention almost every day. By the end, the ones on six hours or less were as bad as people who had been kept up for one or two whole nights. But when they were asked how sleepy they felt, they said only a little. The map said fine. The world said otherwise. That is why so many people tell you they do great on six hours. They aren’t lying. They just can’t see it from inside.

It gets worse. Being awake for seventeen hours slows you down about as much as a blood alcohol level of 0.05. After twenty-four hours, it’s like 0.10, which is over the legal limit to drive in the United States and in most of Europe. Nobody would brag about driving to work drunk. People brag about all-nighters all the time.

I learned this the slow way. For decades I slept badly. It turned out my airway got too narrow at night, and my body kept half waking up to pull in air. I never knew. It took a long time to find, and a jaw surgery to fix. It changed my days. So here is one thing you shouldn’t wait to test. If you sleep enough hours and still wake up tired, don’t shrug it off. Tell a doctor.