How Sleep-Deprived Are You, Really?
This is Dr. Matthew Walker. He’s a neuroscientist and sleep specialist, and is the Director of the Center for Human Sleep Science at UC Berkeley’s Department of Psychology. He’s also the author of the international bestseller “Why We Sleep”.
What does he want us to know?
Sleep deprivation is more serious than many people think it is. After about 16 hours without sleep, the brain begins to fail, and needs more than 7 hours of sleep to “reset” cognitive performance.
Note: note “seven or more”, but “more than seven”.
After ten days with only 7 hours sleep (per day), Dr. Walker points out, the brain is as dysfunctional as it would be after going without sleep for 24 hours.
Here’s the study that sparked a lot of Dr. Walker’s work:
Importantly, in Dr. Walker’s own words:
❝Three full nights of recovery sleep (i.e., more nights than a weekend) are insufficient to restore performance back to normal levels after a week of short sleeping❞
~ Dr. Matthew Walker
See also: Why You Probably Need More Sleep
Furthermore: the sleep-deprived mind is unaware of how sleep-deprived it is.
You know how a drunk person thinks they can drive safely? It’s like that.
You do not know how sleep-deprived you are, when you are sleep-deprived!
For example:
❝(60.7%) did not signal sleepiness before a sleep fragment occurred in at least one of the four MWT trials❞
Source: Sleepiness is not always perceived before falling asleep in healthy, sleep-deprived subjects
Sleep efficiency matters
With regard to the 7–9 hours band for optimal health, Dr. Walker points out that the sleep we’re getting is not always the sleep we think we’re getting:
❝Assuming you have a healthy sleep efficiency (85%), to sleep 9 hours in terms of duration (i.e. to be a long-sleeper), you would need to be consistently in bed for 10 hours and 36 minutes a night. ❞
~ Dr. Matthew Walker
At the bottom end of that, by the way, doing the same math: to get only the insufficient 7 hours sleep discussed earlier, a with a healthy 85% sleep efficiency, you’d need to be in bed for 8 hours and 14 minutes per night.
The unfortunate implication of this: if you are consistently in bed for 8 hours and 14 minutes (or under) per night, you are not getting enough sleep.
“But what if my sleep efficiency is higher than 85%?”
It shouldn’t be.If your sleep efficiency is higher than 85%, you are sleep-deprived and your body is having to enforce things.
Want to know what your sleep efficiency is?
We recommend knowing this, by the way, so you might want to check out:
Head-To-Head Comparison of Google and Apple’s Top Sleep-Monitoring Apps
(they will monitor your sleep and tell you your sleep efficiency, amongst other things)
Want to know more?
You might like his book:
Why We Sleep: Unlocking the Power of Sleep and Dreams
…and/or his podcast:
…and for those who like videos, here’s his (very informative) TED talk:
Prefer text? Click here to read the transcript 😎
Want to watch it, but not right now? Bookmark it for later 🔖
Enjoy!
