Monday 3 July 2006

Pic of the day: Why is Tenko sleeping in the kitchen? Perhaps it is because teenagers need 10 hours of sleep, while their brain is being rebuilt, but instead they sleep 6 hours like adults. No wonder they fall asleep everywhere.

Sleep

I could need some of that, but instead let me entertain you with my latest impressions from the frontiers of sleep research. Some exciting news have surfaced lately.

Perhaps most shocking is a study of more than a million adults for 6 years. It shows that people who sleep 6-7 hours a night have a lower mortality (risk of death) than those sleeping more than 8 hours. Likewise the increased mortality from taking sleep pills seems to be roughly the same as smoking a pack of cigarettes a day. How can this be, if sleep is good for you? Or isn't it?

Actually this is the kind of "study" I love to hate, because it doesn't have randomized control groups. It just shows statistical correlations, not what is cause and what is effect. It is not like they have taken two groups of people and made one of them sleep more and the other less. Rather, the people who sleep more do so because they choose to, or because they can. For instance, people who work probably have less time to sleep, since work tends to take out about a third of your day. That's hard to make up for, and so they are probably over-represented among those who only sleep 6-7 hours. If you study the risk of death in two groups, one of which is working and the other not, you will obviously get results that have very little to do with sleep and very much to do with the reason why they are not working in the first place. Or, in the USA, the poverty that follows from not having a job.

Likewise, people who take sleeping pills don't do this because they picked an even number instead of an odd. They presumably have a reason for it. How then can you compare their health to that of another group that does not have those reasons? The comparison with smoking falters at the starting line. I am sure if you compare people who have surgery scars with people who don't, you will find differences in health too. But those differences probably go back further than the scars.

***

All in all, modern brain research has not opened up all the secrets of sleep, as we may have expected. But some contours seem to take shape. For instance, the deep sleep that dominates early in the night (or day, if that is when you do your long sleep). This early sleep seems to be the most important for the body. This is where growth hormones are released, for instance. It is also important for "fixing" experiences into long term memory, a role which we recently thought was the job of REM-sleep, the vivid dream sleep.

So why do we sleep more than 3-4 hours? Actually, some people don't. It seems to be partly a matter of habit, but also this extra sleep seems to be for the soul more than the body. It brings up memories and associate them with other memories, also useful for long-term memory. And it regulates mood. In most people, the early dreams are most negative, while the late dreams are positive. In a common form of depression, it is the other way around. These people benefit from not sleeping so long, or at least suppressing the REM cycle of their sleep. But with most people, the "extra" sleep keeps them happy, and losing it makes them cranky at best, dangerous at worst.

Another group of people who can do with less sleep is those who meditate deeply each day. By deep meditation I mean altered states of consciousness, not just relaxing by idly thinking or daydreaming. So- called "emptiness meditation", which goes beyond ordinary thought, can have this effect. I assume the meditation is the key here, but in truth we do not really know. It could be other factors in their lifestyle, which is hardly usual. Or there could even be certain traits these people are born with, that make them more likely to meditate and less likely to sleep. More research is in order. At least meditation is something people can choose voluntarily. Or at least some of us can. Actually it can be taught, but it comes naturally (even automatically) only to some.

***

While there is constantly some sleep research going on, you will find very little nap research. Yet naps can save human lives, quite literally. Especially if you sleep less than your optimal quota, and especially if you keep doing this over some time, you will grow extremely tired during your wake time. This may only last for some minutes, or it could be longer. But it makes it extremely hard to stay fully awake and alert. If you however have the opportunity to take a brief nap, you rewind the equivalent of a couple hours sleep, temporarily, in 5-15 minutes. So pull over and get those minutes.

In its most bare-bones form, the "power nap" is done sitting while holding some object in your hand. The object should be chosen for its ability to wake you up when it falls. I have found an empty soda bottle to be fine. You may also tie something to your finger with sewing thread, this is even better than sound at waking you up. Also it won't alert anyone else, in case that is a concern. On the other hand it is kinda visible if you are suddenly interrupted. Anyway, you nap until the object falls from your hand and wakes you. Actually you need not ever fall that deeply asleep, just having it there to assure you that you won't fall asleep in earnest may be enough. Or perhaps that's just me.

It is kinda creepy to consider that most trans-Atlantic and other long flights don't have provisions for napping by the pilots, even though these things seriously mess up their sleep schedule. Studies show that at the end of such flights, the pilots have "microsleep" – loss of consciousness for one or a few seconds – on and off during critical operations like landing. The body was simply not constructed for intercontinental flying, it was made for a completely different life and no matter your motivation you still have a human body. I believe that if napping stopped being taboo, many human lives could be saved, as well as various limbs. And fortunes from bad business decisions as well.

Or you could, I suppose, sleep the night until you wake naturally. But that sure takes a lot of time.