Read this, and have a good night’s sleep!
Sleep that knits up the ravell’d sleeve of care,
The death of each day’s life, sore labour’s bath,
Balm of hurt minds, great nature’s second course,
Chief nourisher in life’s feast.-
William Shakespeare- Macbeth
I have been giving wrong advice to my patients! Often, they ask me, ‘How long do I need to sleep?’ and I tell them, ‘It depends, different people have different needs for sleep but on average six to seven hours is fine.’
Matthew Walker a sleep expert, in his book Why We Sleep: Unlocking the Power of Sleep and Dreams, summarises 25 years of sleep research. The book’s contents are startling with profound implications for our lives.
All animals that have a life span of more than 24 hours sleep go into a cyclical state resembling sleep. As an evolutionary process it does not make sense that all animals should enter a stuporous state every day making them vulnerable to predators and environmental harm. Sleep must serve some essential function or evolution would have weeded out all organisms that sleep. To quote Doctor Allan Rechtschaffen, a noted sleep scientist, ‘’While we sleep, we do not procreate, protect or nurture the young, gather food, earn money, write papers, …If sleep does not serve an absolutely vital function, then it is the biggest mistake the evolutionary process has ever made.”
How many hours do you need to sleep? The World Health Organization and the National Sleep Foundation (NSF), two respected scientific bodies, recommend an average of eight hours of sleep per night for adults and nine hours for teenagers. Well, actually they recommend a range. Here are the details given by the NSF.
Pre-schoolers (3-5): 10-13 hours
School-aged children (6-13): 9-11 hours
Teenagers (14-17): 8-10 hours
Younger adults (18-25): 7-9 hours
Adults (26-64): 7-9 hours
Older adults (65+): 7-8 hours
Are we getting enough sleep? There are no statistics available for Sri Lanka,but two-thirds of adults of all developed nations do not sleep the recommended eight hours at night. And I suspect that few of our teenagers studying hard for examinations, playing video games or browsing the internet get their minimum of nine hours sleep.
We, humans, are the only species that deliberately deprive ourselves of sleep. What are the consequences of not getting sufficient sleep? I think you are going to be shocked by the answer.
The shorter your sleep, the shorter will be your life span. Familial Fatal Insomnia (FFI) is a condition related to mad cow disease. The person afflicted usually in their forties, find it increasingly difficult to sleep. Eventually, the person cannot sleep at all. The person wastes away and death brings a merciful end within a year. No treatment will help. Don’t worry you are unlikely to get it. It is a very rare condition but illustrates how badly we need sleep. There are less dramatic ways in which sleep deprivation will shorten your life.
A study by the American Automobile Association in the US showed that if you drive on less than five hours of sleep, your risk of an accident increases threefold. On less than four hours or less the previous night, you are 11.5 times more likely to crash. So, think and get a good night’s sleep before you get up early morning to beat the traffic and exit the city to go on that vacation.
Decades of research can now give the answers we did not have till now. The runtime of the human brain is sixteen hours. After that, it begins to fail. We need more than seven hours sleep each night to maintain optimum brain performance. If we get even a little under seven hours of sleep for ten days at a stretch, our brains are dysfunctional as it would be after 24 straight hours of sleep deprivation. Think you can catch up on the weekend? I am afraid you can’t. You need three full nights of recovery sleep to restore the brain to normal levels,and that is more than a weekend.
Vehicle accidents due to sleepy drivers exceed those caused by alcohol and drugs combined. Drowsy driving on its own is worse than driving drunk. You may find that a surprising statement. There are two ways drowsy driving can cause an accident. The first, is by completely falling asleep at the wheel. This is uncommon unless you have gone without sleep for a day or more. The second, more common, and I am sure many of you all have experience, is a very brief period of sleep lasting just a few seconds during which your eyes fully or partially close.
During this period called a microsleep, you are completely unaware of your surroundings. If you have a two second microsleep at a moderate 60 km/h your vehicle will be without control for 33 metres. On a highway, at 100 km/h it will be 55 metres. If you veer off course that would be sufficient to crash onto the barrier or into oncoming traffic probably killing you and several others besides you. A drowsy driver is worse than a drunk driver as a drunk driver reacts slowly but a drowsy driver during a microsleep cannot react at all.
How else can lack of sleep shorten your life? There is evidence that sleep loss inflicts devastating damage to the brain and is linked to several neurological and psychiatric conditions such Alzheimer’s dementia, stroke, depression, bipolar disorder and anxiety to name a few. A large multi-country study showed that progressively shorter sleep increases the risk of death from coronary heart disease by 45 percent. The impact is more as we age. Middle-aged adults sleeping less than six hours per night are 200 percent more likely to have a heart attack compared to those sleeping an average of seven to eight hours per night.
Lack of sleep increases blood sugar, the risk of diabetes and leads to weight gain and obesity. In a study, testosterone levels dropped sharply in a group of healthy young men who had less than five hours of sleep for one week. Men who sleep too little have 29 percent lower sperm count and end up with significantly smaller testicles compared to well-rested males. Poor sleep can lead to significant subfertility in women too.
Inadequate sleep impairs our immune system and makes us vulnerable to infection. Influenza and the common cold leading to pneumonia is a significant cause of death especially in the elderly.
Poor sleep increases the risk of cancer.It is related to a variety of tumours such as cancer of the prostate and colon, but the strongest link is to breast cancer. Denmark became the first country to pay compensation to a woman who after years of night shift work developed breast cancer. The International Agency for Research on Cancer of the World Health Organization now classifies shift work as a probable carcinogen.
There are many reasons to sleep,but many do not or cannot get adequate sleep. The benefits of sleep far outweigh any possible benefit you might get by burning the midnight oil (more like to be LED lights nowadays).
Shakespeare was right, sleep is indeed the chief nourisher in life’s feast. So, if you have finished reading this article and it’s night-time, please go to bed.