How much sleep do we really need to work productively?

Depends upon during which period you sleep. E.g. if you sleep between 10/11pm to 6/7am, which is the best period to sleep IMHO, then 7-8 hours is very good.

But even if you sleep 10 hours from 2am to 12 in the afternoon, it's far from enough or healthy.

A siesta is a nitro pack. Don't miss that in the game; especially if you live in a hot climate. I feel like blessed with a lot of bliss after I rise form my nap in my office sick bay(dorm/resting room/whatever) (I'm already smiling :-) ). My manager doesn't appreciate my 30-45 min nap everyday after lunch, I don't give a damn!

>>will be sleeping 24 years in our lifetime.

Indeed. So will we be peeing. So, what about recycle the water and keep it in our system itself. Will save the time of drinking water and then peeing. Double bonanza! This is absurd. You can't live life by remaining awake for longer period. For one, your life shortens and number and period of sunsets, sunrises and rains will not shift towards more if you start remaining awake more.

>>“Sleeping 8.5 hr. might really be a little worse than sleeping 5 hr.”

Now, either my biological clock needs a fix and everybody I know around me or his. Really.

My personal sleeping habit: I sleep at 11/12pm and almost everyday wake up at 6/7am. I never set an alarm unless either I've a VVI appointment - like with a doctor, a meeting or a flight to catch.

It's my personal belief that humans need to sleep as long as their body wants too. I'm the "No alarm clock" type of guy, and when I'm very tired from a long week of short sleeps and exhaustive work, I sleep a lot more the first night of the Weekend, and the day after compensate and sleep less, with no planning whatsoever of my sleeping time. So I usually sleep 8 hours before waking up, and I feel great, I don't know why. What I do know, is that if I set up an alarm to wake me up before that time, say 90 minutes earlier, I would feel bad for a good part of the morning. I'm quite sure a lot of people (the average people) are experiencing the same natural time span of sleep. Hence the "myth" that 8 hours are good for you. On a side note, my father sleeps a lot less than I do, and most people do, and I can honestly say that he's more tired than the average person in his surroundings. Now that might be linked to stress, but I'm quite convinced that a lack of sleep induces stress, so...

I've noticed that taking a sleep aid, regardless of the amount of sleep I actually get, is actually helpful for feeling rested when I wake up.

For instance, last Saturday night, no sleep aid, I fell asleep around 5am, woke briefly at 10am, and woke completely at 1pm for a total of 7 hours. Last night, I took some AdvilPM (instead of my usual 3mg melatonin) at 10:30p, was in bed by 11p, and woke up this morning around 8a.

This might be because the sleep aid actually pushes me into waking up at the end of a REM cycle; I can't ascertain that. But I've found that the amount of sleep I get basically doesn't matter. Before I started with the sleep aids, it was random and infrequent for me to feel rested. I've been taking them for about a month now and it's sort of amazing how much better I feel.

(Also, as an aside, the first sleep aid I tried a year ago, a tablet of Unisom, did absolutely nothing for me. Also, 5mg melatonin seems to be too much for me. More data points.)

> But even if you sleep 10 hours from 2am to 12 in the afternoon, it's far from enough or healthy.

Why? Are you suggesting that the later in the day I fall asleep, the less healthy the sleep becomes?

My favorite sleep anecdote is that if you take some rats and force them to not sleep (put them on a treadmill and wire them up to some electrodes that will start the treadmill up and keep them awake whenever they start to doze) the rats will die within a week or so. Shorter than it takes to die of dehydration. Something about the brain overheating.

Sleep is a big deal, and not just because of the memory issue. Brains are expensive!