If ever there were a puzzle and a blessing wrapped together in the same blanket, it is sleep. A third of life is given over to it; without it we go mad; it is the best healer, soother, painkiller and friend if it comes, but the worst tormentor if it stays away. Poets and philosophers praise it; Ovid likened it to the fallow year of arable land, which produces its best crop afterwards, and Schopenhauer believed that the more you sleep the longer you live.
This last point is controversial. There is some evidence that afternoon naps shorten life. As always, there is also some evidence that it does the opposite. The best evidence is what one’s own body says; and if it says a snooze after lunch feels right, then it is.
The sleep patterns of famous people are intriguing. Churchill slept in two short bursts, the first in the pre-dawn and the second in the afternoon. Lady Thatcher is said to have scarcely slept at all, and some would say it showed. As we age we sleep less, subconsciously aware that we are soon to sleep for ever.
Studies of sleep indicate that one of its purposes is bodily self-repair and, in childhood, growth. But its chief reason seems to be mental organisation; sorting memories, securing what has been learned, resting the brain from the barrage of external data it receives while awake.
The big puzzle is dreaming. Scientific study of dreaming is known as oneirology, and one of its chief findings is that electrical activity in the brain during most dreams resembles waking activity, and is accompanied by rapid eye movements – we dreaming humans do with our eyeballs what sleeping dogs do with their paws and whiskers. Oneirologists suggest that dreaming is for ‘synaptic refreshment’ in the brain – synapses are the connections between nerve cells – and that bizarre dreams are therefore indicators of ‘accumulated synaptic efficacy errors’.
That might be right, but it misses the romance. One does not have to believe, nor should one, that dreams are prophetic (though in Freudian fashion they might reveal deep dark aspects of ourselves) to appreciate the amusement they offer, even if sometimes the terror too. Nightmares are commonest in childhood and in stressful times; that suggests dreams have psychological and not only neurological uses. They amaze us sometimes; and sometimes we find that during them we can fly; with drunkenness and madness they are the origin of religion.
Scientists and laymen alike agree that none of us sleeps enough. Without a good eight hours asleep, our sixteen awake will never be as good as they could and should be – which any good night’s sleep proves.