Why we sleep
The new science of sleep and dreams


A comprehensive and detailed book with a lot of scientific depth about sleep. We learn what it takes to fall asleep and how to do it faster, and the catastrophic consequences of sleep deprivation.

Beauty sleep

Start off with a little fun fact about the phrase and old saying “beauty sleep”. It was put to the test by a group of scientists. They asked a bunch of students to get two good nights of sleep, then a picture of them was taken,  a week later, they were asked to get only 4 hours of sleep for two nights straight, a picture of them was again taken. Next, they asked a total of 122 strangers to have a look at the photos and rate them on attractiveness, the sleep-deprived picture scored lower on attractiveness, compared to the photo where they had gotten two good nights of sleep. The conclusions here are pretty clear, if you want to look a little less ugly than usual, go get a good night of 8 hours of sleep. 


The birds, the wind, and the eagles 

There are two main factors that determine your sleepiness level and how fast you will fall asleep. The first one is a chemical called adenosine. When waking up, your adenosine levels in your brain will be (if you had a good night of sleep) very low. Throughout the day, it will increase in concentration with every waking hour, the more adenosine in your brain that is attached to the sleepiness receptors, the sleepier you will feel.

Can look at this process as birds(adenosine) flocking to a crooked mast, when the mast falls, you fall asleep, the more birds on the mast, the more likely it is to fall down.

The second factor is our inner twenty-four-hour clock known as circadian rhythm, that regulates the sleep-wake cycle, and in the driver seat for this cycle is melatonin. After sunset, the rise in melatonin production begins and starts flowing through your bloodstream, basically screaming to your body, it’s dark, time to sleep.

In our crooked mast metaphor, circadian rhythm and melatonin are the wind blowing on the mast trying to make it fall, the more melatonin on our body, the more powerful and strong the wind is, which increases the probability for the mast to fall. 

One of the most damaging things against falling asleep and the quality of sleep is caffeine. When entering the brain, it starts to fight, with success, against adenosine for the same place at the sleepiness receptors, and will make us more energized, instead of sleepier.

We can look at caffeine as eagles, chasing away all the birds from the crooked mast, and prevents it from falling.

But the more alarming with caffeine, it will take 5-7 hours to remove half of the caffeine from your body. So, if you take a cup of coffee, pre-workouts, etc. around 1800, half of that amount will still be present, battling the birds(adenosine) when trying to sleep around 23-0000. And when you do fall asleep, the battle will continue, resulting in a reduced quality of sleep.

Some pitfalls regarding caffeine you might fall into, are eating chocolate and having a coke zero in the evening, cause, after all, you do deserve it after a long day at work behaving like a proper human being. In reality, you are just screwing yourself over. Both chocolate and coke zero contains a surprising amount of caffeine. Another one is pre-workouts in the evening, which is a large dose of caffeine that will absolutely kill all possibilities of a good night of sleep.


Two key factors in the production of melatonin are sunlight and temperature. When the sun goes down, our eyes will get a reduced amount of sunlight, when it happens the melatonin production will increase. in today’s society, we surround ourselves with a massive amount of artificially light from lamps, computers, mobiles, TV, etc. All the light will drastically hamper the production of melatonin.

A study conducted to compare the melatonin in the body when reading a printed book vs a book on an iPad. Reading on an iPad suppressed melatonin realize by over 50%, and delayed the rise by up to three hours compared to those why were reading a printed book.

Another key factor is core body temperature, when lowered during the evening, the melatonin production increase.

A good start to increase melatonin production is to dim your light in the rooms where you spend your evening, before going to bed take a hot shower (for reduced body temperature), put your electrical devices in another room, reduced the room temperature to around 18-19 degrees, read a book, and when trying to sleep have a completely dark room.


Why do we need sleep?

A good 8 hours of sleep is a miracle cure and the most effective way to reset our brain and body each day.

When sleep-deprived, a lot of bad things will happen to our brain and body, it’s like a domino effect that will spread like a wave of damage throughout your body, and the first thing to go is our concentration.

With a bad night of sleep, the connection between the amygdala (emotional brain center) and the prefrontal cortex (rational, logical thoughts and decision-making) is reduced or even lost. The consequence is less impulse control, more extremes swing of emotions, both negative and positive. The sleep-deprived brain will also have more difficulty recognize socioemotional signals, and distinguish one emotion from another, like facial expression (angry, happy, sad) and body language, which will make social interaction harder. You will basically have a reduced emotional IQ when sleep deprived.

Sleep plays a key role in memory aid. When sleeping, our memory that is stored in our short-term memory bank (hippocampus) is transferred and saved in the long-term storage sites(cortex). The hippocampus is now ready for more information, and the information that we learned the day before is saved with a good night of sleep.

Sleep on it might be something you have heard when stuck on a problem. The reason is that sleep will fuel creative thinking and can be a problem solver at night. When sleeping your current problem will start bouncing around your entire back catalog of memories, trying to find a comparable problem. When awake, you might have found a solution to the problem or come up with a whole new original idea.

The two hormones Leptin and ghrelin are involved in governing your desire to eat. Leptin signals a sense of feeling full, ghrelin does the opposite. And yes! You guessed it, when sleep-deprived, the concentration of the hormone that makes you feel hungry(ghrelin) increases, and Leptin decreases. The result: you yearn for more food, not only that since your thoughtful decisions making center (prefrontal cortex) is muted, you will likely go for more sweets than usual. The weight-gain train is in motion.

In a study done at the University of California, where 150 healthy individuals were divided into groups. One group slept less than 5 hours, another 5-6 hours, one 6-7 hours, and the last one 7 hours or more, then everyone was given a dose of the rhinovirus and closely monitored. The result where staggering, the group with less than 5 hours had an infection rate of almost 50%, the group who slept more than 7 hours had only 18%. So, with less sleep, you have a reduced immune system and are more prone to catch a cold.


The reason for getting a good night of 8 hours of sleep are endless, the book covers even more reasons and goes into great detail about every single one.

I will summarize some easy steps you can do to improve sleep and fall asleep faster. Start with dimming your lights in the evening, have a cold bedroom, reduce mobile and TV use 1-2 hours before bed, read a book instead, be extremely careful with caffeine intake, regular training or some sort of physical activity and try to have a strict bedtime schedule(go to bed a the same time every day).