I get my kill at (*) people who describe sleeping as "dangerous" by these figures. Unhealthy people need more sleep, but that doesn't mean it's the sleep that makes them unhealthy! But I'm not surprised about the finding that oversleeping affects cognitive performance -- I can't be the only one here who's noticed that staying in bed leaves me lethargic all day. (*) An idiom meaning "I find it very funny". Compare "laugh at", "die laughing", "kill myself laughing".
If you have insomnia to any degree, or a non-24 hour cycle, then trying an experiment to find your "optimal" number of hours to sleep is almost impossible. And if you take any sleep aids then obviously that throws a wrench in the effort too.
I'm from Central Scotland (Stirlingshire). My Dad's originally from further east (lived near Falkirk and Edinburgh in his chilhood) and he says it too. My mum is not Scottish, and I don't recall ever hearing her say it.
It'd be interesting to see the history behind this saying. I've been able to find some reference to "kill" originally meaning "very funny", but no pointers to the etymological origin. R. ==
I'm going to hazard a politically incorrect guess and say that Cainntear descends from violent antecedents like Picts, Celts and Vikings, who relished in killing their enemies, i.e. thought it was fun.
I grew up in Stirlingshire (although my parents aren't from there) and I don't remember ever hearing that expression... interesting one. Anyway I agree with Peregrinus: insomnia's a problem for me, and since more often than not my sleep pattern is messed up to some degree and I have a backlog, it's hard to figure out what an optimal amount of sleep is. Too many variables. But the times when I am "caught up", I find that around 7 hours is fine. I'm curious to try out one of these devices that tracks your sleep, I'm sure the results would be interesting.
You can get a sleep logger for a smart phone. You lie it next to or under your pillow and it uses the motion sensors to track your deep sleep (no movement) and shallow sleep (tossing and turning).
I've been exercising a lot lately, so I consider that to be a good excuse to get a little more sleep (maybe an extra hour). But under my normal routine, with my normal amount of exercise, 7 hours is about right. I seem to need less sleep as I grow older, or maybe I just can't sleep as long as I used to.
