>>I read till I go over the same section again and again, then realise I haven't taken it in. Then I put down the book and drop off immediately. Otherwise I'm a life-long semi-insomniac. I'm more or less indefatiguable.
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>Some people like my sister in-law need 5-6 hours sleep. My wife, if she can get it will sleep for 10 hours. When I was a teenager I could sleep for 12-14 hours.

I've come down to pretty stable 8 hours. Occasionally, it happens that I sleep just 6, 5 or even 3 hours - which I then make up by sleeping 15 minutes in the afternoon. I don't really know how I do it, but this power nap does work for me. It's usually on the carpet, with just a minimal pillow, and I sink deep within a minute. In the evening, it usually takes me much longer to get asleep.

I have a different problem. My day seems to have 25 hours. When I don't pay attention (don't ask how much), I tend to go to bed one hour later every day. Then I usually have to break out of it, usually when I come close to 3am mark, by forcing myself to wake up early, be slightly dizzy for a day, and then be sort of normal for a while.

BTW, "fall asleep" is another funny expression -- no English word for "zaspati" (start sleeping).