Gillian Doran reviews Stanley Coren's Sleep Thieves
A review
for the New Scientist
Stanley Coren's Sleep Thieves takes this spirit of `carpe noctem' as the starting point for a wide-ranging exploration of sleep, sleeplessness and its effects on our lives.
Sleep may be a comfortable state for most of us, but it is not visibly productive - and from the moment the electric light banished forever our need to make our work time dependent on the hours of daylight, our society has moved closer and closer to twenty-four hour shopping, working and entertainment. Coren takes the bulk of his examples from America where this phenomenon is particularly noticeable, but while the British may not be quite sure why one would need a hairdresser at three in the morning, we aren't far behind in demanding the option.
Few would deny that this lifestyle is appealing - who hasn't wished for a couple of extra hours in the day from time to time? And, in their absence, who hasn't taken a couple of hours off the night's sleep, just until we achieve some goal at work or home. For a few days, this is fine, although we'll have a `sleep debt' to pay off by the time the weekend comes or the deadline is met. Some researchers take this idea further, suggesting that the normal eight hours may actually be more than we really need to maintain our health and well-being - an idea which Coren, a self-confessed workaholic, admits to having jumped at. He includes in Sleep Thieves a series of extracts from his diaries, charting his progress over a matter of weeks, towards a goal of five hours' sleep a night. It is both instructive and fascinating to watch this attempt founder under a torrent of absent-mindedness, garbled papers (he was receiving uncomplimentary feedback on work from this period for several months afterwards) and uncontrollable dozing - including whilst driving. Reduced sleep, it seems, is not a viable option.
In fact, the ideal seems to be quite the opposite - it appears than most of us, given the choice, would sleep rather more than eight hours a night. This comes as no surprise to those of us who will happily stay in bed until eleven o'clock on Sunday morning, but consider how difficult it is to make yourself sleep when you are actually well rested. Statistics gathered at the Antarctic research base have shown that if people are left to their own devices, in the absence of clocks and changes of daylight to tell them when they should sleep, they will gravitate towards a pattern of around ten hours' sleep in every twenty four, often in the form of a long `night' sleep and a shorter (two or thre hour) `siesta'. It is worth noting that the siesta is institutionalised in many countries, to the extent of being enshrined in law in China.
These results seem to imply that we are all suffering from a lack of sleep - and our performance may be suffering as a result. One US Army officer, training new recruits, experimented with extending their sleep from the Army's normal seven and a half hours to nine hours a night. He found that their performance in all categories immediately increased by almost ten percent. In best army style, he was then called in by his senior officers and given a severe talking-to for ``mollycoddling'' the recruits and turning them into ``fat housewives'' and ``out-of-shape technicians''. He returned his recruits to their normal sleep pattern, performance dropped back to its previous level - and at his next evaluation, he received an ``unsatisfactory'' rating, because his classes' scores had dropped ten percent ``for no apparent reason''.
These relationships between sleep and performance may seem unimportant to those of us who work from nine to five and can choose, with only minor inconvenience, how much sleep we get. But the issue becomes crucial for those who hold responsibility for others' lives - airline pilots and air traffic controllers, drivers, and most famously, junior doctors, who may be expected to work shifts of up to thirty six hours (some of this nominally on call), and to cope on an average of less than five hours' sleep a night. Studies show that this type of sleep deprivation plays a large part in accidents and other poor performance, whether making mistakes with simple calculations, failing to notice vital data, or doctors falling asleep in the operating room. This can be caused by direct lack of sleep, or by the broken sleep and constant readjustment of the biological clock caused by shift work. It has been shown that even shift type can affect performance. The Philadelphia police, who operate on three eight-hour shifts, had their shift pattern changedfrom an eight day clockwise rotation to an eighteen day clockwise rotation, and achieved a 25-30 percent reduction in sleeping on the job, and a 40 percent overall reduction in accident rates.
If you wish to apply these findings to your own life, you should note one thing. People are not good reporters of their own sleep patterns. Most of us have had the experience of complaining to a partner that we didn't sleep a wink, only to receive a baleful look and the information that they didn't sleep because we were snoring. Coren takes this a step further, with an anecdote about waking one morning with his wife and agreeing that neither of them had had any sleep - and gradually realising, as consciousness dawned, that the bed was covered with plaster, the result of a small earthquake which both the Corens had slept through. One can't help but get the impression that Coren's sleep experiences are so odd he had to get into the area as a researcher.
Be this as it may. Coren's approach to these issues around sleep is one of evident concern, but he skillfully avoids any hint of polemic. Instead, the reader is given a broad overview of sleep, both medical and sociological, that guides them gently towards the conclusion that we (Americans in particular) are living in a ``sleep deprived society''. While we may complain that we do perfectly well on our seven or eight hours, it is hard to dispute Coren's facts, though a little more medical detail and hard science would have been useful. One suspects, however, that these details may not yet be available, and his emphasis on the sociological and the personal certainly makes for engrossing reading. Science has only ruffled the edges of sleep - its true nature remains as mysterious to the scientist as to the dreamer.
