ELi5: Experts say you can’t “pre-sleep” and also can’t catch up on lost sleep; what exactly does that mean? Since it’s not like I feel tired for the rest of my life after missing a night’s sleep, after a few days of good sleep I’m back to normal.


Does “not being able to catch up on lost sleep” mean that every night of lost sleep accumulates to a shorter life span, more illness, or something of the sort?

In: Biology

I think it comes down to trying to chase lost sleep almost. For example if you stayed up all night one time, you may then have the urge to sleep for 12 hours instead of your usual 6. The saying typically means that having 12 hours of sleep won’t really give extra benefit because you cant have the missed night of sleep back

I read a science article a while back about this. If I can find it again I’ll post it here. The gist of it was that our brains sort of ‘wash themselves’ while we’re sleeping. If you don’t sleep long enough, your brain isn’t squeaky clean the next day. This not only impacts your immediate health the day after a bad sleep, but can also result in long-term damage if poor sleep is a chronic habit. Just like there’s no point in washing dishes that are already clean, you can’t pregame sleep and expect your brain to cooperate. Similarly, if you ran dishes for a half-cycle every time you put them in the dishwasher, those plates are gonna be gross.

Edit: Here it is: https://www.theatlantic.com/science/archive/2017/02/the-brains-connections-shrink-during-sleep/515472/

I take it to mean that there is only one optimal or “right” amount of sleep for a specific person, regardless of the situation.

If your body functions best with 8.5 hours of sleep, that will be true every night, regardless of how many hours you got (or failed to get) the night before. So if you stay up all night and feel exhausted, the solution is to get 8.5 hours of sleep, not 10 hours. Accordingly you can’t “bank” sleep by getting 10 hours the night before you plan to miss some hours. You’ll still be just as tired or even more so, because 10 hours exceeds your optimal amount.

I think this is mostly true. I worked in the film industry for many years, and often got 3-5 hours of sleep during the week. If I tried to over-sleep on the weekend, to make up for it, I didn’t feel much benefit. Around 8 hours was best. Although there is a caveat, that I found after a week of little sleep, it was harder to get restful sleep. I would end up staying in bed for 10 hours, with a few hours of restlessness interrupting the actual deep sleep.

That was what they thought until recently at least. New research suggests you can catch up on lost sleep. You can heal your brain once you get into REM sleep again, it may take a long time depending on big your deficit is to catch up to but it’s definitely possible.


They mean you can’t sleep for a week, and then stay awake for a week. Being awake drains your batteries, and you can run on empty, but your battery only holds so much power. You can’t pre fill it to last longer. And if you run on empty for really long, it’s still the same battery you’re charging.

I’ve answered this question before. But here goes.

Don’t muddle together long term sleep deprivation with short term. That’s where the confusion sets in.

We don’t truly understand exactly why we need sleep. But we know that sleep is important for clearing out metabolic waste in the brain and hormone regulation, one of the most important being cortisol, or for the purpose of this discussion, stress.

In the short term, say a single poor nights sleep, you’ll be tired the next day as your body is attempting to tell you to “fix” the problem. Sleeping extra the next night will correct the problem. Maybe even just a normal full nights rest will fix it without extra sleep.

Now say it’s been a year and you have slept 5 hours a night ever day. This does permanent damage down to the cellular level. Your body has been unable to properly regulate itself because you have disrupted a key process. No amount of extra sleep will fix it. We have found studies relate this type of behavior with early dementia and various chronic diseases.

True ELI5: in the short term you can make up for sleep loss, in the long term the damage is already done and is beyond just sleeping more.

In the same way you can’t charge your phone to 200% if you’re going to be away camping, you can’t get more sleep before a long day to avoid being tired, and you can’t get extra sleep afterwards to recover. Sleep needs to be constant and reasonably measured in order to be healthy both mentally and physically.

It’s like being dehydrated. You can’t drink more water to make up for being dehydrated in the past. At some point you are just hydrated again…anything more doesn’t really help and it doesn’t change that you were dehydrated.

You can extend this analogy to pre-drinking. Yes, you can absolutely make sure you have adequate intake before you do something strenuous, but there is a limit. At some point you are just hydrated. If you tried to drink 8 gallons then go without for 72 hours you’d run into issues.

Well, I don’t know what experts you were reading about, but BuzzFeed isn’t from expert. It’s scientifically proven a known that within a 7-Day cycle, you can catch up on your sleep within that time frame.

Going months with severe insomnia and suffering sleep deprivation, can cause permanent damage, you can’t not sleep for a month and then catch up on it, but if you lose let’s say 12 hours of sleep in a week within those seven days of starting to miss time sleeping, you could sleep those extra hours, and catch up. It’s about your body requiring a certain amount of time to be in rest mode, for deep healing and Body Repair. As well as to comprehend, analyze, and store information gathered in the day.

But, within a 7-Day cycle of losing sleep, you can sleep the same amount of hours to catch up

From my understanding, REM is like a purge and sleeplessness ruins memory and learning. If you go without sleep long enough, you can hallucinate. As far as I’m aware this is mostly reversible damage but you obviously won’t get memories back.

Experts do NOT say you can’t catch up on sleep. It may take several nights to make up a sleep deficit but you certainly can do it. Read about it in this book: [https://www.amazon.com/Promise-Sleep-Medicine-Connection-Happiness/dp/0440509017/ref=sr_1_3?dchild=1&qid=1628536891&refinements=p_27%3AWilliam+C.+Dement&s=books&sr=1-3](https://www.amazon.com/Promise-Sleep-Medicine-Connection-Happiness/dp/0440509017/ref=sr_1_3?dchild=1&qid=1628536891&refinements=p_27%3AWilliam+C.+Dement&s=books&sr=1-3)

Great question!!! There’s nights I’ll get 2hrs of sleep, the next day/night I’ll stay up, the next night ill get 3hrs, etc…. Somewhere along the line I’ll legit CRASH for 24hrs (periodically waking up to use the bathroom or grab a drink.)……… Also sometimes that mixture feeling of not being asleep, or awake, and just laying in the bed for a couple hrs..