Yeah this is one of those oft repeated pieces of advice that has never made sense to me. It's always worded such that it sounds like the effects of any sleep deprivation ever are permanent.
You'll learn less in your sleep deprived states, Which are days you aren't going to get back. Your sleep deprived self will also be better at creating tech debt, which takes away time from the future.
That's not what a description of what the professor says in the article, or the way we mean it.
Of course you won't get "chances to learn" or "tech debt" back. This is not about it. TFA talks about a physiological debt that you can't repay.
From that point of view, all injuries are permanent.
By not sleeping, you magically turn some fraction of the previous day's learning into wasted time, just throw it away.
The appropriate analogue in the twisted ankle case would be if the twist magically "un-walked" the 4 miles you walked the day before, and that increment of weight loss and cardio health were lost to you. This is of course not the case.. :)
I saw this analogy upthread, and it's changed how I consider sleep deprivation. Brain injuries may not be different from physical injuries.
Most significant injuries I've sustained since my early 20s have not let me completely forget them, in spite of them being "fully healed".
Obviously that can be corrected over a few days period and you get back to normal (except if you had abused yourself will lack of sleep over many years, in which case you might have indeed incurred some permanent damage).