I had a two day long migraine in 1995 and have been like it ever since. Never had a migraine after that one either. Had my nut stuffed in an MRI and nothing showed up. My neurologist said he's at a loss. No complaining though.
I can go on 5 hours once in a while and be okay, but I have to make it up later.
I would LOVE to be able to perform well on 4 hours.
Do you feel fully rested after 8 hours? The reason I ask is because some people simply need more than 8 hours, but have thetendency to think that 8 is the "correct" amount to sleep. I had a couple friends who were like this and when they started sleeping ~9 hours they had a marked improvement in all of the symptoms of sleep dep (energy, focus, etc etc).
I've definitely told people this in the past and had negative reactions ranging from the mild disbelief "You're serious, how can that be possible? I don't believe you" to the outright offended "What is wrong with you (as a person)? Why would you want to spend so much time sleeping? That's wrong and ridiculous behaviour".
I do find it curious how some people tend to get really uppity about this issue. As though one's sleeping habits are reflective of character and morals, or something, rather than just being a natural trait which differs person to person and which one has no choice in. Where does this come from?
I've been told point-blank that I just need to change my attitude because, according to this person, my inability to wake up refreshed with anything less than 9 hours of sleep is 100% because of my attitude.
I have relatives who are morning people who act like they're personally offended that I sleep 10 hours on Saturdays.
EDIT: Also, people confuse sleeping late with sleeping too much. If you go to bed at 4AM, getting up at Midday isn't so crazy.
This isn't normal? :P
But seriously, if I don't set my alarm, I usually sleep about 12-16 hours. When I do wake up, it's often because of my bladder / stomach / limb-falling-asleep, and not because I feel rested. Waking up is not enjoyable regardless of how much sleep I get, 2 hours, 12 hours... I'm always a zombie-like, groggy mess. But 30 minutes later I feel great and full of energy, again, no matter how long I slept.
This is day-after-day too, and not just when I'm sleep deprived. Over the Independence Day 3-day weekend, I definitely slept more than 12 hours each day.
Then something changed a few years ago...I'm 42 now, so I think it started when I was 38...I now sleep 6 hours a night, sometimes even 7! It has seriously cut into might reading-for-fun time. I really wish I could go back to 4 hours.
If I'm in the process of learning something complex, I get the distinct feeling of absorbing "fully" the content when I sleep well; whereas if I don't sleep well it doesn't seem fully "processed" yet.
So my optimal sleep schedule varies by what kind of work I want to do. Do you just perform nominally at everything sleeping 4 hours?
I for one notice that I "learn" a lot while sleeping. For example, when studying for an exam, difficult exercises often seem to get much easier over night.
1. My bowel has no idea what is going on half of the time so no routine there.
2. Snoring when I do sleep. This has caused a number of problems with the wife and neighbours.
3. I can't drink alcohol at all. I end up with a 3 day long hangover even if I have a single beer.
Otherwise nothing else.
Edit: Just to add a big downside. I had to spend some time in hospital after a physical injury. There is nothing more psychologically damaging than near insomnia immobile in a hospital bed.