Tuesday 29 September 2015

FMP: Science of Sleep

As my fmp project is about something that helps people, or rather, reminds people to sleep on time. I think this is a good chance to explore things about this activity we do for about third of our entire life.
Sleep is a naturally recurring state of mind characterized by altered consciousness, relatively inhibited sensory activity, inhibition of nearly all voluntary muscles, and reduced interactions with surroundings. It is distinguished from wakefulness by a decreased ability to react to stimuli, but is more easily reversed than the state of hibernation or of being comatose. Mammalian sleep occurs in repeating periods, in which the body alternates between two highly distinct modes known as non-REM and REM sleep. REM stands for "rapid eye movement" but involves many other aspects including virtual paralysis of the body.

During sleep, most systems in an animal are in an anabolic state, building up the immune, nervous, skeletal, and muscular systems. Sleep in non-human animals is observed in mammals, birds, reptiles, amphibians, and fish, and, in some form, in insects and even in simpler animals such as nematodes. The internal circadian clock promotes sleep daily at night in diurnal species (such as humans) and in the day in nocturnal organisms (such as rodents). However, sleep patterns vary widely among animals and among different individual humans. Industrialization and artificial light have substantially altered human sleep habits in the last 100 years.

The science today still unable to answer the question of why do human need to sleep,  Some believe that sleep gives the body a chance to recuperate from the day's activities but in reality, the amount of energy saved by sleeping for even eight hours is miniscule - about 50 kCal, the same amount of energy in a piece of toast. And there are some other explanations too yet it is unlikely anyone of then is the single answer but all contribute a bit to the real answer. 

It seems like sleep does not really contribute much in anyway that is significant enough, however, sleep deprivation could lead to some serious consequences. If you've ever pulled an all-nighter, you'll be familiar with the following after-effects: grumpiness, grogginess, irritability and forgetfulness. After just one night without sleep, concentration becomes more difficult and attention span shortens considerably. 

With continued lack of sufficient sleep, the part of the brain that controls language, memory, planning and sense of time is severely affected, practically shutting down. In fact, 17 hours of sustained wakefulness leads to a decrease in performance equivalent to a blood alcohol level of 0.05% (two glasses of wine). This is the legal drink driving limit in the UK. In the US, more than 200000 car accidents are caused by sleepy drivers, killing people more than drunk-driving. It does not take long before brain and body could feel the result of sleep deprivation.

Sleep deprivation not only has a major impact on cognitive functioning but also on emotional and physical health. Disorders such as sleep apnoea which results in excessive daytime sleepiness have been linked to stress and high blood pressure. Research has also suggested that sleep loss may increase the chance of obesity because chemicals and hormones that play a key role in controlling appetite and weight gain are released during sleep.




Useful Links:
http://www.bbc.co.uk/science/humanbody/sleep/articles/whatissleep.shtml
http://phys.org/news/2011-02-why-do-we-sleep.html
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3385863/
http://www.scientificamerican.com/article/how-long-can-humans-stay/
http://science.howstuffworks.com/life/inside-the-mind/human-brain/sleep1.htm
http://harvardmagazine.com/2005/07/deep-into-sleep.html




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