Where Do You Go When You Sleep?

[00:00:00]Throughout our lives, we spend more than 200,000 hours sleeping, which is almost 26 years or nearly 1/3 of our lives. And the strange thing is, during that time, we almost disappear from the world. The body is still lying in bed, the heart is still beating, the lungs are still breathing, the brain is still working, but you, the feeling of existing, observing, and living in this world seems to shut off, then suddenly returns the next morning. Sometimes, you come back with a strange dream. Sometimes, 8 hours pass by like a blink. And sometimes, you wake up feeling as if you have just been somewhere you cannot name. That is why human curiosity about sleep has lasted for thousands of years, from ancient civilizations, philosophers, and theologians to modern laboratories with 21st century brain scanners. So, when you close your eyes every night, where do you really go?

[00:00:50]Welcome back to Apex. Today, we will follow the most mysterious journey human beings go through every night. To answer the question of where our mind really goes when we fall asleep, the first step is to take apart a default belief that almost everyone thinks is true. It is a misunderstanding that has existed for centuries. The belief that when you close your eyes, your body and brain are simply resting, and sleep is nature's way of helping the body recover. But, if we look at it from the perspective of biological evolution, this explanation reveals a huge gap. Imagine you are a living creature in the wild tens of thousands of years ago. When you fall asleep, you completely lose awareness of your surroundings. Your muscles relax, your vision shuts off, and your hearing drops to a very low level. You become completely helpless and unable to defend yourself. For any animal, willingly entering an unconscious and unprotected state for 7 to 8 hours every day would be extremely dangerous. A deer that sleeps too deeply could become prey for predators. A primate that loses awareness for too long could fall from a tree. If sleep were only for resting the body and saving energy, why did evolution not choose a safer way? For example, simply lying still, relaxing the body, but still staying alert enough to observe the surroundings. The fact that nature forces us into such a risky state proves that sleep is not just recharging the battery. Something else must be happening. A process so important that the body is willing to trade its own safety in order to carry it out. And to understand that process, we need to look at what really happens inside the brain when you close your eyes. When you go to sleep, you do not simply drift into an empty void. Sleep is actually a rhythmic journey divided into two main states that switch back and forth throughout the night.

[00:02:37]Non-rapid eye movement sleep, or non-REM, and rapid eye movement sleep, or REM. When you first doze off, you enter the non-REM stage. During this stage, your heart rate slows down, your body temperature drops, and your brain waves gradually become calmer and longer. Your body is truly relaxing and focusing on repairing physical cells, restoring the immune system, and rebuilding muscle tissue. This is the stage where the idea of rest shows up most clearly. But, after moving through the cycles of deep non-REM sleep, a sudden shift happens. You enter REM sleep. And what scientists discovered next was even stranger. During REM sleep, if someone looked at you, they would see your eyeballs moving quickly under your closed eyelids. Inside your skull, your brain is not resting at all.

[00:03:26]Brain scans show that electrical activity in the brain bursts with intensity, power, and chaos. Almost the same as when you are fully awake and focused on solving a difficult problem.

[00:03:37]The brain is consuming a huge amount of oxygen and energy. And yet, right when the brain is working at its most intense level, it sends a signal down to the spinal cord to freeze your entire body.

[00:03:50]All of your voluntary muscles, except the eye muscles and breathing muscles, become temporarily paralyzed. Why does this safety lock exist? The answer is simple. During REM sleep, the brain creates extremely vivid images, experiences, and dreams. Paralyzing the muscles is the brain's way of protecting you, stopping you from acting out what is happening in your dreams. If you dream that you are running away or fighting, the paralysis keeps your body still in bed instead of suddenly getting up and running into something. And sometimes this mechanism has a small error. If you suddenly wake up but the brain has not unlocked your muscles yet, you enter a state where your mind is fully awake but your body cannot move.

[00:04:28]Guess what that is. That is the phenomenon known as sleep paralysis, which people often talk about in folk beliefs. There is no supernatural force involved. It is only a delay of a few seconds between your brain and your muscle system. If the brain has to work at full power during part of the night, then what exactly is it busy doing? Try to imagine that your brain is a computer. From the moment you wake up until the moment you go to bed, you take in a huge amount of information. You read the news, answer emails, see hundreds of faces on the street, hear bits of conversation from the table next to you, feel the air temperature, and remember the tasks you need to do. Every single one of those experiences, even the smallest one, creates new connections between neurons called synapses. If the brain kept everything you saw and heard during the day, it would quickly become overloaded, run out of storage, and collapse into the chaos of junk data. Modern science has discovered that one of the core functions of sleep is a process of deep cleaning and reorganizing the brain.

[00:05:29]When you sleep, the brain begins to review all the neural connections created during the day. It does something extremely decisive. It removes weak and unimportant connections, such as what you ate for breakfast or the color of the shirt worn by someone who drove past you, and it strengthens important connections, such as new knowledge you learned or a new skill you practiced. This process helps the brain clear space and optimize energy, so you can continue taking in new information the next day without becoming overloaded. Sleep does not only clean up information, it also cleans in a literal sense. In 2013, researchers at the University of Rochester discovered a remarkable mechanism and named it the glymphatic system. They observed that during deep sleep brain cells actually shrink by up to 60% creating space for cerebrospinal fluid to flow through.

[00:06:22]This fluid acts like a flushing system washing away metabolic waste and toxins that build up in the brain throughout the day, including protein plaques linked to Alzheimer's disease. Sleep is not the moment when the brain shuts down. It is the moment when the brain repairs itself, cleans itself, and organizes itself again. This leads to a troubling question. Is the brain's process of mixing and cleaning information at night the source of the strange dreams we see when we close our eyes? For thousands of years, dreams were seen as something mysterious, a message from the future, a spiritual sign, or a doorway connected to another world. But from the perspective of modern more practical and specific role.

[00:07:05]When the brain reorganizes information and memories during REM sleep, it does not work silently. It connects old and new memory fragments, suppressed emotions, and random thoughts together.

[00:07:19]Dreams are the way our conscious mind sees the data processing work happening in the background of the brain. But dreams are not just random disorder.

[00:07:27]They act like a natural form of psychological therapy that happens every [clears throat] night. During the day, you may face pressure, anger, confusion, or anxiety. The brain uses dreams to create a safe virtual reality space. In that space, it tests and processes these complex emotions without having to face any real-life consequences. For example, if you are worried about an important presentation during the day, you may dream that you are standing on a stage but completely forget your script. If you experience psychological trauma, the brain may replay that event in different forms. This is the mechanism behind nightmares. Nightmares are not signs of bad luck. They are often the result of the brain trying to process a large amount of stress, tension, or unresolved fear from your waking life. It is trying to digest those negative emotions.

[00:08:17]Besides that, we also have vivid dreams.

[00:08:20]Dreams that feel so sharp and real that when you wake up, you need a few minutes to realize they were only dreams. These dreams often happen when the brain is highly active during the final REM cycle of the night, creating emotional and connected stories that combine your deepest desires with your real-life experiences. Our brains have been programmed to carry out this cycle of sleeping and dreaming since the earliest days of human life. But, have you ever wondered, why do modern people find it harder and harder to sleep? And why do they seem to have more nightmares? Very likely, the answer lies in the fact that we are forcing our bodies to sleep in a way that goes against our biological design. Most modern people share one standard belief about sleep. An adult should go to bed, close their eyes, and sleep straight through for 8 hours without interruption until morning. If you often wake up suddenly at 2:00 or 3:00 a.m., toss and turn, and cannot fall back asleep, you may panic and think you have insomnia, an anxiety disorder, or a problem with your nervous system. But, if we look back at history, the standard of sleeping straight through for 8 hours is actually very new. Historian Roger Ekirch from Virginia Tech spent 16 years studying hundreds of documents from the Middle Ages, from personal journals and medical records to works of literature, And he discovered a shocking truth. Our ancestors did not sleep straight through the night. They had a habit called segmented sleep. In the past, people usually divided sleep into two parts.

[00:09:47]They went to bed at dusk right after the sun went down. Then they would naturally wake up around midnight and stay awake for 1 to 2 hours. This period of being awake in the middle of the night was seen as completely normal. What did people do during that time? They lay there thinking, prayed, talked to the person next to them, read books by candlelight or simply relaxed. After that, they felt sleepy again and entered their second sleep until dawn. In other words, waking up suddenly in the middle of the night may not be an illness or a biological error. It may very likely be a call from your ancient nervous system, a habit that has been programmed into human DNA for thousands of years. So, what changed everything? It was the arrival of artificial light, electric bulbs, and especially the Industrial Revolution. When factories began operating, human work schedules were forced into fixed time structures.

[00:10:38]People were pushed to gather all their sleep into one single block of 7 to 8 hours to fit daytime work shifts. Alarm clocks and blue light from screens tricked the brain and disrupted the natural circadian rhythm. Our living environment has changed too quickly compared to the speed of our body's evolution. Your body was not designed for the rhythm of modern life. It is being forced to adapt, and this forced adaptation has consequences. Rates of chronic sleep deprivation, anxiety, depression, and physical exhaustion are rising. We stay up later, sleep less, and take away the most valuable time the brain needs to do a job that is extremely important for human psychology. Something else happens when you sleep, something deeper than cleaning memory or restoring energy. It is the reset of your own psychological identity. According to the groundbreaking research of Dr. Matthew Walker, a A of neuroscience and psychology at UC Berkeley, REM sleep acts like a perfect emotional filter.

[00:11:37]When you go through a bad event during the day, getting criticized by your boss, breaking up with someone you love, or arguing with a friend, your brain stores that event together with a very high level of stress hormones such as cortisol. You feel hurt, angry, and emotionally suffocated. But when you enter REM sleep, a chemical miracle happens. During this stage, the brain actively stops producing norepinephrine, a chemical linked to stress and anxiety.

[00:12:05]This means the brain takes painful memories from the day and processes them in a completely calm chemical environment without panic. Sleep separates the negative emotional layer from the memory. It helps you remember the event, but with much less emotional pain. That is why people often say, "Just get some sleep, things will feel different in the morning." Science has proven that this saying is completely true. When you wake up the next morning, the event is still there, and your memory of it is still intact, but the emotional weight pressing on your chest has become much lighter. The brain has automatically cooled down your emotions while you were completely unconscious.

[00:12:42]Every night, through the process of filtering out unnecessary memories, strengthening new knowledge, and adjusting emotional intensity, the brain is quietly reshaping your perception of the world and of yourself. Your attitude toward a person, your reaction to an event, the way you judge a difficulty, all of these can change after a long sleep. So, in the end, when you close your eyes every night, where do you really go? The answer is you do not go to another dimension, and you do not wander into an imaginary world. You go inward. You enter the maintenance and editing room of your own mind. This leads to a troubling thought, but also a very fascinating one. If consciousness, your thoughts, personality, emotions, and memories is what makes up you, then every night this process is temporarily paused. Your consciousness disconnects.

[00:13:34]Your identity dissolves into dreams, neural impulses, and quiet waves of cleaning that happen in the dark. During those hours, the brain automatically decides which pieces of memory get to stay, which information gets thrown away, which fears need to be soothed, and which emotions need to be changed.

[00:13:52]It sharpens and rebuilds your thinking system. Then the sun rises. You open your eyes and consciousness returns. You step out of bed and naturally believe that the person who just woke up is the same person who went to sleep last night. But in reality, from the perspective of neural connections and psychology, the version of you from yesterday no longer exists in its original form. A new version has been updated, carrying softened emotions, selected memories, and a slightly different neural structure, officially stepping into a new day. Sleep is not shutting down. Sleep is the process in which we continuously break ourselves down and build ourselves back up again.

[00:14:28]Thank you for watching today's video from Apex. What do you think about our journey every night? Do you often wake up in the middle of the night or have vivid dreams? Leave a comment and share your thoughts below. Don't forget to hit like, subscribe to the channel, and turn on notifications so you do not miss the next journeys into psychology. Goodbye and see you again.