Tuesday, February 21, 2006


Earlier this year I read William Dement's, The Promise of Sleep, Random House 1999 which discusses what sleep is and how people manage their sleep. I found the discussion of sleep debt interesting - burning the candle 'catches up with you'. Many people have sleep disorders that doctors don't know much about it. Moreover, many medical problems seem to be related to sleep. If you snore, and particularly if you are overweight, you probably have a health problem. Issues such as obstructive sleep apnea (where breathing is severely disrupted while a person sleeps) is a quite serious medical disorder that can be addressed by surgery or CPAP sleeping masks. People can suffer ongoing medical problems for years that are primarily driven by sleep deprivation. Many car accidents are caused by mini-sleeps, a fact now addressed in much Australian road safety propaganda. If you have not slept for 17 hours you are about as prone to a car accident as someone driving with a blood alcohol level of 0.05. But generally, for something that is such a major part of our lives, relatively little is known about sleep. We don't really know why we sleep and why it is necessary.

By the way, Dement's advice if you have a short-term insomnia is not to agonise over it but to take a standard sort of sleeping pill such as one of the benzodiazepines. Don't agonise over it and don't feel 'sinful' - just be aware that with sustained use these can be very addictive.

NewScientist this week (# 2539, subscription only) has 2 articles on sleep. The first is a note summarising evidence that the hormone melatonin is useless for increasing sleep. Nor is it useful for dealing with jet-lag , as popularly supposed, as a review of 25 studies recently confirms. I have tried it several times myself on long trips from the US and I found it either had no effect or gave me a slight headache.

But , in a second-article, Graham Lawton in this NewScientist suggests a new batch of drugs will conquer sleep and to enable us to be active for up to 22 hours per day.

One drug is Modafinil which is claimed to allow you to stay awake for 48 hours with no ill effects. It is a eugeroic drug that creates wakefulness without the jolt that stimulants give. You don't feel more alert, you just don't feel tired. Moreover you do not incur sleep debt. If you wish to sleep you can.

Sales of Modafinil have climbed from $25 million to $575 million from 1999-2005. While initially prescibed for narcolepsy and sleep apnea, it is clearly now being used for 'lifestyle' reasons. An issue is whether illegal markets will develop for diverted supplies of this drug.

While the indications are that Modafinil is safe the mechanisms that make it effective are not understood. It prevents neurons from reabsorbing the neurotransmitter dopamine once this is released into the brain. But beyond this not a lot is known. And, of course, its long-term effects are unknown. The obvious question that occurs to me is that people who take such drugs are assuming that sleep does not have a crucial function for which no effective long-term substitute exists.

But circadian biologists like Russell Foster envisage a world where it is possible, or even routine, to be active for 22 hours a day and sleep for 2. Would the Liberal Party legislate for twice daily 8-hour work shifts (assuming capital stocks cannot be operated more intensively, output/labour ratios would remain the same with output doubling) or could we work all night and enjoy ourselves during the day? But would we want to live such lives even if it were possible?

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