Why Do We Sleep?

Singapore sleeping uncle

The single most important behavioral experience that we have, is sleep. If you’re an average sort of person, 36 percent of your life will be spent asleep, which means that if you live up to 100, then 36 years will have been spent entirely asleep. 36 years should tell us that sleep is an important activity in our life. Unfortunately, most of us don’t think about sleep. We rarely think about his importance and its value. Throughout history, the way we see and value sleep has changed.

Thomas Dekker,  in the 1500s, said: “Sleep is that golden chain that ties health and our bodies together“. If we step forward few hundreds of years, Thomas Edison had a totally different view  “Sleep is a criminal waste of time and a heritage from our cave days.” And of course, we all remember the infamous quote from Gordon Gekko in “Wall Street” who said “Money never sleep”

Nowadays we use Thomas Edison’s light bulb to invade the night, and it is like we tolerate the need for sleep. At worst, many of us think of sleep as a kind of waste, an enemy to fight. While you’re asleep you don’t eat. You don’t drink and most of us, don’t have sex. So is it sleep a complete waste of time?

Sleep is an incredibly important part of our biology, and neuroscientists can explain to us why it’s so very important. When you’re asleep, your brain doesn’t shut down. In fact, some area of the brain are actually more active during the sleep state than during the waking state. Personally I believe that the most interesting thing about sleep is that it doesn’t arise from a single structure within the brain, but it is to some extent a network property of different structures (Suprachiasmatic Nuclei) and essentially, sleep is turned on and off, like your alarm clock, as a result of a range of interactions in the brain. The name of this clock is Biological Clock. This clock essentially tells us when it’s good to be up and when it’s good to be asleep.

There are many different theories on why we actually sleep but two of those are really fascinating.

The restoration Idea

Essentially, all the stuff we’ve burned up during the day, we restore, we replace, we rebuild during the night while we are asleep. It’s fashionable because what’s been seen is that within the brain, a whole raft of genes have been shown to be turned on only during sleep, and those genes are the ones associated with restoration and metabolic pathways. So there’s good evidence for the whole restoration hypothesis.

Brain Processing and Memory Consolidation

What we know is that, if after you’ve tried to learn a task, and you sleep-deprive yourself, the ability to learn that task is smashed. It’s really hugely attenuated. So sleep and memory consolidation is also very important. However, it’s not just the recalling of memory. What’s really exciting is that our ability to come up with new solutions to complex problems is hugely amplified by a night of sleep. Sleeping at night also enhances our creativity. Basically what seems to happen inside our brain is that the neural connections that are important are linked and strengthened, while those that are less important tend to fade away and be less important.

Sleep deprivation

Huge sectors of society are sleep-deprived, in the 1950s, good data suggests that most of us were getting around about eight hours of sleep a night. Nowadays, we sleep one and a half to two hours less every night, and for teenagers, it’s even worse. They need nine hours for full brain performance, and many of them, are only getting five hours of sleep.

Around 20 percent of the working population does shift work. Unfortunately, the body clock does not shift to the demands of working at night. It’s locked onto the same light-dark cycle as the rest of us. So when the shift worker is going home to try and sleep during the day, desperately tired, the body clock is saying, “Wake up. This is the time to be awake.” So the quality of sleep that you get as a night shift worker is usually very poor. As consequence, one of the things that the brain does is indulge itself in micro-sleeps, involuntary falling asleep, and you have essentially no control over them. Now, depending on the situation, micro-sleeps can be sort of somewhat embarrassing, but they can also be deadly, especially if you are driving.

When you’re tired, and you lack sleep, you have a poor memory, you have poor creativity, you have increased impulsiveness, and you have overall poor judgment. Furthermore, if you have a “tired” brain, the brain is craving things to wake it up. Drugs and other stimulants. Caffeine represents the stimulant of choice across much of the Western world. Much of the day is fueled by caffeine.

If this is not enough, tired people are massively stressed. And one of the things of stress, of course, is a loss of memory. But stress is so much more. So if you’re acutely stressed, not a great problem, but it’s sustained stress associated with sleep loss that’s the problem.

How do I know whether I’m getting enough sleep?

Well, it’s pretty simple if you need an alarm clock to get you out of bed in the morning, if you are taking a long time to get up, if you need lots of stimulants, if you’re grumpy, if you’re irritable, if you’re told by your work colleagues that you’re looking tired and irritable, chances are you are sleep-deprived. Listen to them and more important listen to yourself.

How can I improve my sleep?

The first thing is to make your bedroom as dark as you possibly can, and also slightly cool. Very important. You should also reduce the amount of light exposure at least half an hour before you go to bed. Light increases levels of alertness and will delay sleep. Turn off those mobile phones. Turn off computers. Try not to drink caffeine too late in the day, ideally not after lunch.

Our attitude toward sleep is so very different from a pre-industrial age. We used to understand intuitively the importance of sleep. If you have good sleep, it increases your concentration, attention, decision-making, creativity, social skills, health. It also reduces your mood changes, your stress, your levels of anger, your impulsivity, and your tendency to drink and take drugs.

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