Sleeping your way to the top

We have all experienced that feeling of mental tiredness, grumpiness and irritability that can come after a poor night's sleep. But did you know that not getting enough sleep can also affect your ability to make decisions, your speech, your reactions, your attention span and even your health.

The reason sleep is so important is that the brain appears to work in a similar way to a rechargeable battery - it can function perfectly well for a certain amount of time before needing to be "recharged". Exactly what happens during this recharging period is not fully understood, but some aspects of it are known.

Rapid Eye Movement (REM), for example, is the period of sleep when our brains transfer our short-term memory to our long-term memory. To do this our brain appears to cycle through our long-term memory to find associations with our recent experiences, in much the same way as you would if you were doing the filing in your office. Possibly it is this process of calling memories into our consciousness that is the source of our dreams.

Another function of sleep appears to be to recharge the brain's sensitivity. In 2002, a study by the University of California found that during REM sleep the neurotransmitters (whose purpose is to amplify the signals that pass between neurons and other cells) became inactive. Their conclusion was that this allows the brain's receptors to rest and regain their optimum sensitivity. It is thought that when we get overly tired it is the lack of sensitivity of these receptors that can make us feel fed-up or even depressed.

So sleep is important, but how much sleep is necessary?

A research study involving more than a million participants at the University of California revealed that people who sleep for 6-7 hours a night lived longer than people who sleep for more than 8 hours or less than 5. However, while the evidence was clear that there was an association between the length of time a person slept and their life-expectancy, it was unclear as to where cause and effect lay. In other words, it is not clear as to whether your health affects your sleep or whether it is your sleep that affects your health.

Other studies seem to support the finding that 6-7 hours of sleep per night is optimum, but this will obviously vary from person to person. For example, Margaret Thatcher famously managed to get by on just 4 hours a night, while the actress Penelope Cruz claims that nothing less than 15 hours a night will do!

But how do you know how much sleep you need? Professor Russell Foster of Oxford University has found that many people who suffer from the symptoms of sleep depravation are unaware of the fact as they "do not feel tired". He points out that the average amount of time that people sleep for in the UK has fallen from around 8 hours in the 1960s to around 6 hours today and that if this trend continues we will turn into a "zombie nation", with sleep deprivation harming our metal dexterity, memory and health.

The irony is that our 24x7 economy is increasingly dependant on factors such as innovation and mental alertness, but our lifestyle appears to be leading us to spending less and less time asleep, thereby impairing the very abilities we need to be successful.

However, for those that wish to be successful, this knowledge gives a whole new meaning to the phrase "sleeping your way to the top".

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Published: April 2010

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