Understanding Sleep

Dhanak Gupta

Since the dawn of time,sleep has been considered an essential part of our everyday life. It is known to affect our perception, mood, social life and both physical and mental well-being. However, in the past century, this concept has been widely criticised by famous people such as Thomas Edison in 1921 who wrote, ”sleep as a waste of time, ‘a heritage from our cave days”.  More recently in 1980s, the former British Prime Minister also stated, “sleep is for wimps”.
Scientists are fascinated by the idea ofSleep.They have been thoroughly investigating to find answers to certain key questions like:What is sleep? Why do we need it? How long do we need it for? Is it possible to get away from sleep?How do I know if I am getting enough sleep? In this article, I will try to provide you with the answers known for these and many more prevailing questions:
What is Sleep?
Sleep is the single most important and complicated behavioural experience that we have. Data suggests that an average human being, living upto 90 years, spends 32 years of his/her life sleeping. In spite of this, most of the people in today’s modern society, don’t give it a second thought, consider it a waste of time and some people disregard it to an extent that they consider it as an illness or even enemy. Most people abandon the idea of sleep simply because they believe that we don’t do anything much while we are sleeping. However, Neuroscientists are trying to explain why Sleep is an extremely important part of our biology.
Melatonin is the hormone that induces sleep. During the daytime,when light falls into the eye, it sends neural messages to the brain that stops the production of melatonin, therefore, we are awake. During night time, when we are asleep, there is no transmission of neural signals from eye to brain as there is no exposure to light, therefore, melatonin is released and we sleep.
Why do we need Sleep?
Scientists have come forward with various theories for why do we sleep.  Here, I will outline, two of the most widely accepted theories for the same.
Restoration idea: According to this, all the energy we have burnt up during the day is recaptured, restored, rebuilt and replaced during the night. This concept goes back to the time of Aristotle (384 BC – 322 BC), who first came up with this idea. Recent evidence also shows that indeed there are certain genes which are switched ON only when we are asleep and these same genes are also associated with restoration and metabolic pathways.
Brain processing and memory consolidation idea: Research suggests that the learning ability in sleep deprived individuals is hugely smashed and attenuated as compared to individuals who have had proper sleep. Scientists have also observed that the creativity of individuals and ability to come up with novel solutions to complex problems is enhanced three times by sleeping at night. This tells us that during sleep, those neural connections in the brain that are important tend to consolidate and become more prominent and on the other hand, the less important neural connections tend to become weaker and therefore, fade away.
How long do we need to Sleep?
Neuroscientists have done some Sleep o-meter analysis for different age-groups of people. In 1950’s an average individual was getting 8 hours of sleep every night but in 2012, this number has gone down to 6.5 hours every night. Research also suggests that where teenagers need 9 hours of sleep every night, they are getting only 5 hours of sleep on a school night. If you are aged, your sleep is very disruptive and again you might sleep for less than 5 hours a night. However, there is growing evidence suggesting that sleep requirements do not go down in old age, though it might be fragmented.
Scientific investigations also shows that a lot of accidents, for example, the tragic disasters in 1986 of Chernobyl Nuclear Power Plantin Ukraine and Space Shuttle Challenger disaster in Florida, USA and various car accidents around the world, are caused because of poor judgement as a result of extended shift work, tiredness and loss of vigilance of the workers or drivers.
Hence, lack of sleep leads to poor memory, poor creativity, increased irritability and impulsiveness and overall poor judgement.
Is it possible to get away from Sleep?
Almost everyone tries to get away without sleeping by resorting to coffee, tea, smoking (nicotine) or even drugs. And eventually, at night when our brain feel completely wired up and awake, we try to put it to sleep using alcohol. Interestingly, small doses of alcohol at night do seem to ease transition from being awake to sleeping for only a short period of time. However, what most people are not aware of is that alcohol doesn’t really sedate but actually mimics the act of sedation and in the process, is harmful for our neuronal process of memory consolidation and memory recall. Therefore, alcohol is only a short-term acute measure to getting to sleep every night.
Obesity or fatness is another major problem associated with lack of sleep. It has been seen that 5 hours or less sleep every night make us 50% more prone to becoming obese. This is because lack of sleep cause the release of hunger hormone called Ghrelin, which makes the brain to feel the need of carbohydrates, especially sugar. This leads to metabolic predisposition to weight gain.
Stress is also associated with lack of sleep, which often leads to lack of memory. Consistent stress is also found to be connected with lesser immunity and therefore, such people are more prone to infections. There are consolidate evidences to show that diabetes and heart problems are one of the most common problems associated with stress and lack of sleep.
How do I know if I am getting enough Sleep?
If you are not getting enough sleep, your body will show you symptoms for the same. You will feel tired and irritable in the mornings, need a lot of stimulants to wake you up and often your colleagues will pick up on that in your office at work. You might also feel exhausted for most of the day.
There are certain measures that can be taken to make sure you get enough sleep. Firstly, make your bedroom a heaven for sleep: make it as dark as possible and slightly cooled. Reducing the light exposure atleast half an hour before going to bed, decreases our alertness and eases our transition to sleep. On the other hand, seeking out exposure to morning light is a good way of setting your biological clock to the day and night. Secondly, turn off all the mobiles, computers and other devices that can excite the brain before going to sleep as there is an increasing evidence to show that late night exposures to these devices causes sleeplessness. Lastly, try not to drink stimulants like coffee or tea after lunch.
(The author is a Doctoral student Wolfson Centre for Stem Cells, Tissue Engineering and Modeling (STEM) University of Nottingham, UK)