As someone who has spent over 10 years of their career working a shift pattern, 6 years of which included travelling to multiple time zones, I read with interest some of the recent articles in the press regarding the consequences of sleep deprivation.
The first article discussed a self-diagnostic test which focuses on the time taken to fall asleep during the middle of the day. The Sleep Onset Latency Test is a simple one which takes place in a darkened room during day light hours and involves a tea spoon and a metal tray. The teaspoon is held over the tray and a time check is taken before closing your eyes and when the spoon drops from your hand and hits the tray you are awoken from sleep to check the clock again. Falling asleep within ten minutes indicates you find it difficult to get a good night’s sleep, over fifteen minutes is pretty standard but if you are asleep under five minutes you are severely sleep deprived.
So what are the consequences of sleep deprivation and why should we be concerned? The headline for another recent article intimated that being in this state causes the brain to eat itself! Although this may seem like an alarmist approach the health and well-being consequences of sleep deprivation are multiple and are linked to the onset of chronic diseases.
During sleep many things happen within your body, your immune system produces cells to fight off infection and illness but ironically these produced cells – called cytokines –also help you sleep. The central nervous system is afforded a much needed rest during sleep and has time to form new pathways for future use. The heart also takes this time to repair and restore blood vessels reducing the risk of stroke and heart disease. In the bodies of children and adolescents growth hormones are secreted which are obviously essential to development.
Recent studies have also reported hormone imbalances caused by sleep deprivation and found that this state causes a reduced level of leptin in the body. This hormone regulates hunger and this reduction stops the body telling you when it is full, also the secretion of ghrelin, which stimulates appetite, is increased making obesity another risk factor.
Other research has focused on the link between sleep deprivation and dementia and Alzheimer’s. Going back to the thought of the brain eating itself without sleep – the concept, worryingly, is not quite as absurd as it sounds. The brain has three different cells which act as a clean-up crew. These are glial, astrocyte and microglial cells which between them eliminate redundant synapses and search the brain removing damaged cells. All of these cells were found to be much more active after a period of sleep deprivation.
Sleep pattern professionals measure sleep cycles via a method called Polysomnography, using electroencephalography (EEG) which measure the electrical activity of the brain, electromyography (EMG) which measure the tone of muscles in the body and electro-oculography (EOG) – the measurement of eye activity. By tracking these measurements they are able to measure the stages of sleep and interpret them accordingly.
It is human nature to want to self-diagnose and the current market gives us plenty of opportunity to do so. These devices include wearable devices to track movement, heart rate, time in each stage of the sleep cycle and how many times you have awoken, or experienced a period of restlessness, throughout the night. Other devices include mats that can be attached to the top of your mattress to record similar information and even one which collates this data via sonar and does not even need to be in contact with you on your bed. Other manufacturers have focused on devices that measure environmental factors in order to ensure the best conditions to fall asleep in and also alarm clocks that only wake you during your stages of light sleep – allowing you to wake up feeling less groggy.
The accuracy of these devices does vary and there are lots of factors that can skew the results, such as your partner rolling onto the monitor strap or you rolling off of it. Also some devices struggle to distinguish whether you are actually asleep or just completely still.
The over whelming verdict seems to be that the focus on our sleep habits can only be a good thing. These devices, although not as accurate as a professional consultation, can give an overall diagnosis and make us more aware of factors to consider. When you consider the potential health implications of sleep deprivation, an awareness of how we spend one third of our life is essential.
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Julie has written numerous interesting and well researched blogs on a wide range of topics related to Medical Devices and Human Factors. Please click here to read more of Julie's blogs and here to find out more about Julie.