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How Do Genes Determine An Optimal Amount Of Sleep?

Without sleep we could not live. This is the basic need of every living being such as food, water and breathing. It is not enough to sleep just a few hours. Sleep deprivation can lead to a variety of mental and physical disorders. Sleep deprivation significantly reduces our alertness and ability to perform daily activities too.

However, we all know someone who complains that he or she is tired even after 10 hours of sleep, and also someone who is full of energy after only a few hours of sleep. There is growing evidence that it is our genes that determine how much sleep we need. 

Neurologists and other scientists from the University of California conducted a study which proved that mutation to a DEC2 gene affects how much sleep we need.

What is the average amount of sleep for humans?

It is believed that an adult should sleep 7 to 9 hours each day in order to achieve peak performance the next day. Children need more sleep than that, and older adults less. But about 7 billion people live on planet Earth and not everyone can have identical needs.

An image of a bearded man in the first stage of sleep.

The aforementioned DEC2 gene has been known to scientists for decades and is known to regulate circadian rhythm. It regulates the circadian rhythm not only of humans but also of animals. Circadian rhythms are all natural processes in the body that are controlled by shift of light and darkness. Scientists have previously noticed mutations in this gene in mice, but have only now determined that mutations may be present in humans, thus affecting the need for sleep. What scientists have yet to determine is whether this mutation means a person needs less sleep or just can’t sleep long enough.

What is the definition of short sleep?

Again, it is difficult to say what exactly is the definition of short sleep, because different people need different amounts of sleep. Nevertheless, if you constantly sleep less than 6 hours, it is considered insufficient sleep. When you sleep too short for several nights in a row, you create a sleep debt.

Every time you sleep shorter, sleep debt will increase and leave more and more serious consequences on your mind and body. Sleep debt recovery is certainly possible but you will need several days until you get enough rest and reset your body. Short sleep can also lead to other problems such as sleep inertia, delayed sleep phase disorder, microsleep and sleep drunkenness.

Why does short sleep occur?

There are many reasons why short sleep occurs. There is even a name for it – Short sleeper syndrome (SSS). A mutation in the DEC2 gene may certainly be the reason. But one should not immediately assume that this is the case. First you need to consider whether you take care of your sleep hygiene. Virtually anyone can improve sleep hygiene.

An image of a young man suffering from lack of concentration.

Then you should check if there is any underlying medical problem that causes insomnia. Sleep apnea probably won’t kill you, but both obstructive and central sleep apnea are often the culprits for sleep problems. Those who suffer from anxiety and depression usually have worse symptoms in the evening, so nighttime anxiety often keeps people awake during the night.

Does short sleep have anything to do with Alzheimer’s?

According to the Alzheimer’s Society UK and other respectable associations dealing with this disease, there is certainly a link between short sleep and dementia. However, scientists still do not have an answer to the question of what is the cause and what is the consequence.

An image of a young man feeling confused upon awakening.

While some think that short sleep causes dementia, others believe that short sleep is actually an early symptom of dementia that will occur after a few years or decades. And there is a strong possibility that both are true. Once they are sure what is true, it will certainly help the prevention and treatment of Alzheimer’s, and until then it is important to take care of the quality of night’s sleep.

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