The tired brain works harder and remembers less
Sep 17
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You slept badly last night. In a meeting, a colleague shows the new reporting system. You take notes. Afterwards someone asks which report goes to finance. It's somewhere in your notes. You can't find it.
Researchers at McGill University wanted a quick fix for a sleepless night. They kept 53 adults awake for 30 hours.
Then before learning something new, one group took a nap. One group cycled for 20 minutes. One group sat still.
In a memory test, the nappers and cyclists remembered about 20 percent more. As quick fixes it worked, at least for one night in a lab. The third group tried hard. It didn't help.
I think most leaders are in that group more often than they know.
Then before learning something new, one group took a nap. One group cycled for 20 minutes. One group sat still.
In a memory test, the nappers and cyclists remembered about 20 percent more. As quick fixes it worked, at least for one night in a lab. The third group tried hard. It didn't help.
I think most leaders are in that group more often than they know.
Hippo can't keep up
I usually call him Hippo. He is the brain's archivist. Everything new you learn goes to him first. He sorts it and files it. Then you can find it again later.
I usually call him Hippo. He is the brain's archivist. Everything new you learn goes to him first. He sorts it and files it. Then you can find it again later.
After a short night, Hippo works slowly. New information keeps coming in. He doesn't have time to file it all. A lot of it ends up on the floor instead of in the archive.
Corty notices. She is the part of the brain that plans and focuses. She tries to help by pushing harder. You concentrate more. You write more notes. It feels like you are working well. But all that effort doesn't get the information into Hippo's files. That is what happened to the group that sat still. They tried hard. They still remembered less. Effort and memory are two different things. A tired brain can give you lots of the first and very little of the second.
You don't notice it yourself
Few of us stay awake all night. But many of us sleep six hours, week after week. A well-known study in the journal Sleep tested what that does. People slept six hours a night for two weeks. At the end, their brains performed as badly as people who had missed a whole night of sleep. But they didn't feel much more tired. They thought they were fine. They were not.
Few of us stay awake all night. But many of us sleep six hours, week after week. A well-known study in the journal Sleep tested what that does. People slept six hours a night for two weeks. At the end, their brains performed as badly as people who had missed a whole night of sleep. But they didn't feel much more tired. They thought they were fine. They were not.
That is the trap. We judge ourselves by how tired we feel. And the feeling says we can manage one more late evening.
In my book I mention how sleep loss is more than feeling tired. The bigger cost is that your brain doesn't work at full strength while you are awake. So the hour you gain late at night, you pay for the next day. You read things twice. You ask the same question again. You make decisions without all the facts.
First, count your short nights
You can't trust the feeling. So count instead. How many nights in the last two weeks did you sleep less than seven hours? Write down the number. If it is half or more, Hippo has been working slowly for a while.
Then plan for the days after a short night. If you need to learn something new, move your body first. Do 20 minutes of exercise that makes you breathe harder. In the study, that helped memory as much as a nap. If you can, put the new learning on a day after a good night. Afterwards, test yourself. Can you explain it without your notes? If you can't, it didn't go in.
After a short night, we try harder. It feels responsible. Other people may even see it as hard work. But effort doesn't prove that anything went in. So think back on this week. What did you work hardest to learn after your shortest night? How much of it can you still explain?
After a short night, we try harder. It feels responsible. Other people may even see it as hard work. But effort doesn't prove that anything went in. So think back on this week. What did you work hardest to learn after your shortest night? How much of it can you still explain?
/ Maria