I am not a doctor, but I still suspect that your body is catching up on sleep it thinks it needs and the bad feeling after it is due to just switching between modes (switching off your current 5-7 hrs of sleep a night). If so, you will likely need way more than 1 night to transition.

As a personal anecdote: I once slept for 10.5-11 hours a day for about 2 weeks. I decided that I need to catch up on sleep, so I went to bed at 8PM every night, fell asleep by 9 and awoke between 7:30 and 8. After about 2 weeks I stopped falling asleep by 9 and would fall asleep around 11 and wake up at 7, at which time I stopped my "sleep fattening". I did feel like a weirdo going to bed at 8, but it felt great at the end.

YMMV, but if you can sleep for 12 hours a night I would consider letting your body do it for at least several days to see if it would switch to a different mode that your would like more. My 2c.

Another personal anecdote to support this; I’ve done this sort of “reset” more than once, and there is a qualitative difference between getting 9 hours of sleep between 10pm-7am and 1am-10am for me. Your mileage may vary, but that 3 hour shift is the difference between feeling like a winner or feeling like a loser for me. I don’t know if it is psychosomatic, but I also don’t care if it is as long as it keeps me feeling good.

This used to be me. I now realize that the reason for my grogginess was that I was totally dehydrated after my 10+ hr sleeping marathon. I now sleep with a water bottle and try to drink half of it before going to bed. When I do this I find that I will naturally wake up after about 8.5 hrs, drink the remaining half of the bottle, fall back asleep for 30 min, and then wake up feeling great. Wonder if this could work for you too

I, too, keep water by the bedside and drink some before falling asleep. However, the older I get, the less I drink, so I don't wake up every couple hours to pee. The moral of this story: don't get old.

this is true. my bladder wakes me up before most everything else, and it won't let me go back to sleep until it's addressed. I'd love to sleep 8-9 hours a night, but my kidneys have other plans for me.

source: am old.

Try having a look at Saw Palmetto tablets. It’s stopped my dad from having to wake twice in the night to use the bathroom.

I know it's practically sacreligious, but if you drink coffee, you should stop.

Can this be mitigated by keeping the room a bit more humid, so you don't lose as much liquid through your skin?

Especially in the winter, waking up in a room with sub 30% humidity is brutal.

I've found that drinking more water throughout the day has helped my nightly dehydration.

I have a theory that by oversleeping too much your body goes into sort of hibernation mode and wants to preserve energy to the end of the world. On the other by sleeping little and having strict schedule you enter a type of primal survival mode, similar to if you were sleeping outside on savannah, which keeps you alert even with minimum sleep.

I had and have the problem that if I don't put alarm on, I will oversleep and my day gets kind of ruined. So for me I always have to set an alarm and if I feel tired and have nothing on morning I'll maybe bump it by an hour. For me the best sleep schedule is going to bed by 12-2 and waking up between 8:00-9:30. This way if I occasionally stay up till 3-5 my sleep rhythm won't be completely ruined.

I have experimented with various different tricks and styles, recently after a long vacation in different timezone allowed me to completely transform my sleep rhythm. After I came back I woke up automatically 6:00 sharp without any alarm, and I went to sleep 22-23 which was quite bizarre. Sadly though I enjoy late evenings much more than early mornings so even if I went to sleep 0:30 I'd wake up at 6, very tired, which led me to sleep longer and in the end ruining the rhythm.

But what I've found out is, that you want to wake up exactly during the light sleep cycle as that's when you feel no tiredness at all waking up. If you try waking up during REM or deep sleep it will feel like pulling teeth. For me the best time is somewhere around 8 if I go to sleep by 1-2 which counts up as ~7 hours. Should probably track it better but yeah. Also I bought wake-up light alarm clock which is interesting but I don't know yet has it actually an effect.

Although I have to say following an exact schedule is probably the best solution sleep-wise. Decide a time when you have to be at bed and an exact time when you have to wake up, no matter what. I think doing this during my vacation is what caused it to be so ingrained in my body that I was able to wake up at 6 without any alarm.

See, I'm the opposite. Even without the screen time or stimulation, I will fall dead asleep at 10pm, and no matter what, will wake up promptly at 4am.

I feel like there really are people who have different needs.

Agree. I'm in bed between 9-10 every night (later than that is an exception), and read a book on my phone as part of my sleep ritual. My phones DnD comes on at 9 so I do not get any alerts while reading. From when I get in bed to read, to when I fall asleep might be 15 minutes depending on how much exercise I did that day.

I set an alarm for 6am, but even without one I'm up between 6-7.

Personally, I think the key for people who have a hard time sleeping is consistency. If someone is trying to go to sleep at 10pm Sunday through Thursday, but then staying up until 2-3am Friday and Saturday it's no wonder they can't get on a schedule.

> will wake up promptly at 4am.

A possible explanation is that you've trained your body to wake at that time -- but it isn't necessarily enough/appropriate sleep.

Wouldn't there be feelings of tiredness or some kind of exhaustion? I generally feel well rested and chipper all day.

Without those feelings of tiredness, how would you know if it's training or your actual internal clock working correctly?

You might very well be a short sleeper.

This. I haven't used an alarm for close to 20 years, though my cycle is closer to 12 to 6.

Well, that doesn't invalidate my point.

The whole thing is to listen to your body, the problem is when people do 12 to 6 with an alarm, while they'd actually sleep form 10 to 7 without external constraints.

I'm convinced that it's just your body trying to catch up all the sleep it didn't get.

Of course, lying down for a long time will have side effect on your muscles (headaches, groggyness) but I'm sure your body would return to normal sleep patterns after some time.

Why headaches from lying down for a long time?

Dehydration most likely.

One of reasons could be that when you are sleep deprived you have elevated adrenaline and cortisol, which you might got used to.

Check "Why we sleep" recommended elsewhere in this thread if you want to fix it.

If you eat more than 6 hours before sleep you wouldn't sleep 12. Hunger would be happy to wake you up. Learned this and even lost weight. Last meal at 5PM. Waking up constantly at 8AM without alarm (going to bed at 12)

In another the-body-realize-it's-ok-to-open-the-floodgate moment, I would always get really sick after making it through some intense deadline. I think it's just the body finally realizing it's ok to stop constantly keeping everything in turbo mode rather than associating the causation backwards.

I'll echo others who are saying that this could be because you are normally sleep-deprived.

Try to increase your bedtime slowly to 8 hours, maybe 9(but not much more than that) and keep at that for a while. See if there is any benefit.

It is unlikely that you are part of the tiny minority that requires less than 6 hours of sleep, so you should be sleep-deprived with only 5 hours.

Personal anecdote: my sleep patterns were very similar. Until I got diagnosed with sleep apnea. My body wanted more sleep – but the more I slept, the more apnea events I would have. So, I would wake up feeling like death, and with a headache, due to my brain getting starved of oxygen.

Not saying that this is your problem or that there is even a problem, but you could raise this issue on your next checkup. Maybe your doctor will have some suggestions.

Because it is weird, as you rightly point out. Trust your judgement.

As someone who has had a ton of sleep issues over the years this seems like the best advice here, although I would not increase past 8 hours and a regular 7 hours is likely to be fine for most people. Sleep apnea and circadian issues are common and worth considering, but there is a lot of individual variation in sleep so ultimately what feels best to you is likely what is best for you (other than that <6 hours of sleep is not a good idea). Sleeping much longer than usual may trigger circadian issues so it is worth being careful.

In my experience it takes years for circadian changes to stabilize, at least once they are sufficiently disrupted (I have Non-24 and have been able to stop shifting my sleep for over a year at a time but eventually it comes back). At the same time, it seems to me that catching up on sleep is only really possible to a limited extent and only for a couple of days after sleep deprevation no matter how long the deprevation. Getting sufficient sleep for a while after sleep deprevation does seem to help reduce the effects of future deprevation, but I don't think getting extra sleep really helps. Keeping a stable circadian rhythm with suffient sleep is most important.

I suspect that if not something like apnea that 10-12 hour sleep might be due to how sleep is maintained. There is a sleep or awake switch in the brain and also a "maintain the current state" network. To make the shift to awake cleanly, the "maintain current state" system is likely stronger in the morning (on a circadian rhythm, not just "after you wake up") but if you manage to be sleeping at the time it kicks in more strongly it may keep you asleep for hours even without any particular need to be asleep. This isn't necessarily what is actually happening but I think it fits the evidence.

I don't think longer sleep is always worse than the alternative, however I suspect if it feels necessary then it is a sign of a more serious sleep issue and if it doesn't feel necessary then aiming for a regular circadian rhythm with sufficient sleep is a better option.

I would guess at least some of that would be catchup sleep + dehydration from not drinking in 12 hours.

>without an alarm I can sleep 12 hours.

This was the case for me until I started (a) going to bed shortly after dark and (b) leaving the blinds open.

An really incredible thing happened: I started feeling tired around dusk, and awake at dawn.

Note that it's best to avoid/limit screens and LED lights past dark.

Could very well be that you're just leveraging your circadian rhythm coupled with the appropriate sleep stages cycled.

You're likely waking at the optimal time of completion of a complete sleep cycle. That doesn't necessarily mean you're getting enough sleep overall.

I have the same problem. The more I sleep past 7 hours the shittier I feel for roughly the number of overslept hours. If I sleep 12 hours, I'll feel foggy and groggy for 5 hours afterwards (12-7=5). I think it is serotonin related.

I force myself to not sleep more than 7 hours.

It's possible your body is catching up on years of chronic sleep deprivation.

If you can get several weeks of vacation with no alarm, you may find yourself sleeping 10-12 hours a night for a while, but eventually it should decrease.

I used to be like that - until I started my current flexible schedule which allows me to wake up naturally.

Now my body sleeps 8 hours and I wake up the same time every day.

Has anyone managed to break out of this? I've tried increasing exercise, waking up with sunlight; nothing works

I used to have trouble waking up too. What worked for me was having a strict morning routine that I followed the moment I woke up. I found that sleeping 10 or 12 hours wasn't uninterrupted; I'd often wake up briefly in the morning, realize I was very tired, and quickly fall back asleep. Once I had a morning routine, it became my first priority when I woke up to fulfill that routine and would allow me to pull myself out of bed earlier. Typically my routine is to get ready for work Monday through Friday, but this habit of waking up when I've finished sleeping without an alarm also persists through the weekend.

If I stay up later than usual then I'll often wake up at the usual time and just sleep a little less, but sometimes I'll sleep a bit longer. Either way I still feel very tired breaking out of my schedule. I'm also lucky enough to have an employer allows a relatively flexible schedule so I could experiment with this for a while.

A hard cut of caffeine after 10:30 AM, cutting blue light (and screens if possible) after sunset, and if nothing else having a kid can do it.

Or, try camping for a few days. Try not to look at your phone after sunset.

Camping is like an immediate fix for me. You just naturally wake up with the first rays of sunlight.

I think it also helps a lot to move around all day (as one does while camping). I feel so much better.

Or leave the phone at home or at least do not turn it on, unless you need to.

I grew out of it without doing anything in particular

How much is increasing exercise ?

1-2 hours of moderately intense exercise

Do you feel ok if you only sleep 5 hours a night?

Could it be CO2 build-up in your bedroom?

No. Same thing happens if the window is left ajar.