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Getting selected for Special Forces is no walk in the park. Recruits endure experiences that are much too difficult for the average person to even comprehend. In this blog post, Slovenian Special Operation Force medic Luka Zorenč gives a peek into the SF qualification process as he shares a story about what happened when he was deprived of sleep for a period of several days.

In this blog post:


Hello, I am Luka Zorenč, author of the Lynx book.

The book talks about who I am, about my career in the Slovenian Army. I spent most of my time in Special Operation Forces, and in the book I closely describe exactly this path: what selection for SOF looks like, all the psychophysical efforts you go through during the selection process, and how basic SOF training and specialisation are organized. 

I present further specialisation for a SOF medic in the United States, and the missions in Kosovo, Mali, and Iraq. You’ve already met me through the UF PRO TCCC series for people and K9s.

Here is a passage from my Lynx book: 


“The status card is there so that each of you knows exactly who has which equipment at any given moment. You need to know that, as well as me and the commander!”

We started to move across the rolling hills. In the camouflage discipline, we inspected a nearby area to see if the presence of an enemy could be detected. 

We came to a clearing and did a short reconnaissance. We took smaller backpacks out of our larger ones to make moving around easier. 

We moved in circles, squares, or star shapes to inspect the area as thoroughly as possible. We gathered the information and headed back to the starting point. All this information was written in our diary: “Impassable forest” or “No signs of enemy presence.” Then we moved again and repeated the exercise.

All day long, we were walking here and there, looking for the enemy, carrying heavy backpacks, and performing tactical procedures. I understand now how the hobbits from Lord of the Rings felt, I thought to myself.

I was tired, hungry, everything hurt, and I felt dizzy because I was stupid and didn't drink enough water. I was biting my lip so I didn’t fall asleep every time I squatted somewhere, provided cover for a colleague, or checked our location on the map.

Team is inspecting the area.

Just disconnect. I had to push everything aside if I wanted to think clearly. I was learning how to tolerate all the hardships of the world voluntarily.

The task for that day was done. The patrol base had to be set up. When we had been planning the location of the base in the classroom, everything had looked fine.

We only just found out what kind of wilderness we had gotten ourselves into. We crawled up the hill like mules. It might be wise to tie myself to a tree so I don't fall down again.

We finally reached our base, which was like some kind of little shelf in the hill. Some luck was on our side after all.

“Come on, Zoki, check if there's a connection here so we don't get f-ing lost again!” Shrek reminded me. It's nice to have friends! He was serious because he said “f-ing”. I knew what that meant in expanded form. Shrek never cursed and if he did, the situation really was desperate! Basically, he cursed only when he ran out of MRE chocolates.

In case the radio station at the base site wouldn't catch a signal, we would have to move and certainly lose another hour or more.

We started with the priorities. No matter how many external factors there were, the concepts in the military were, in principle, always the same. The concept is always the same! I kept repeating in my mind, even though we were too close together, even though we didn't have proper security set up, even though nothing was as it should have been…

This time, our priorities went a little better. We did everything faster. When it came to food, the selection skills of stuffing ourselves really came in handy.

That’s when I realised there was actually some logic to all this madness. In the constant battle with time, quick intake of calories was essential. Mushroom stew was on the menu this time as well.

After all this, we were really very tired. We cursed each other’s mothers so we could remain awake and still somehow function. After the priorities, it was finally time to rest.

There were 40 minutes of resting left until the hour when the next move had been planned. We worked on everything in pairs. Since both could never sleep at the same time, we divided the roles - each earned 20 minutes of sleep while the other was on guard.

We didn’t ask why that was, why we only got 20 minutes when we would have needed hours and hours of sleep. Pitying ourselves wasn't worth it. We took whatever was given to us.

I fell unconscious. The next moment, it was all over. What's happening? Oh, right, Jesus Christ, I'm here! Okay, time to move. Take the gear and let's go!

We continued with the hobbit odyssey, which did not seem to end due to insomnia, hunger, and general fatigue. We were walking through the area all day and inspected it once using one method, and the second time another, depending on the terrain. The vegetation was no longer as dense. A tall beech forest surrounded us. The area was much more open, so we had to adjust to the new situation.

The backpacks were getting heavier, despite the emptied water bottles. At each stop, we looked for a tree on which we could lean and thus relieve our backs at least a little. We rested only on our knees. 

The backpacks were getting heavier every minute.

No one dared sit on their ass because of the threat of the rewards. Well, the rewards weren't so bad. The minuses written in the notepad hurt the most, and everybody sometimes earned one.

During security, we rarely lay on the ground. It was too hard to stay awake if you weren’t doing anything. For the most part, we all crouched on our knees. I was biting the insides of my cheeks to keep myself awake. I was constantly tasting blood in my mouth and licking the wounds.

We were getting more and more tired. We leaned on hills to relieve our knees a little and rest our bodies. I calculated that my backpack should have been at least 10 kilograms lighter given the amount of water I had drunk. It still hurts carrying it around. I set my head on autopilot. Breathe. Keep going forward. The task needs to be done.

While investigating the area, we unexpectedly received quite a few “parachute” tasks from command. We had to establish various connections. Then we had to think about how to logically organise ourselves among all the tasks we had to complete.

Before nightfall, we occupied the new patrol base and started taking care of priorities. 

The more time passed, the more there were of those who were standing while guarding. We've already started sleeping while kneeling …

Team was sleeping on their knees

I stood on guard and moved away from all the nearest trees. If I lean on a trunk, I'll fall asleep standing … I loosened the belt with which my rifle was fastened so the weapon just hung loosely next to me. I was guarding my sector and getting a bit lost in my mind. Suddenly, the rifle fell out of my hands and hit me on the knee. The pain woke me up in an instant. But I didn't  fall asleep!

I gripped the rifle tighter. I woke up again with the feeling of falling. I was probably rocking back and forth, but when I started to fall, my defense mechanism activated and woke me up.

The next priority was cleaning the weapons. I was holding the rifle in my hands when I noticed that I was squatting in the middle of a snake's nest. 

Why are there thousands of intertwined snakes below me? Why are they crawling all over my gear? They were hissing a few centimetres away from my face. I tried to grab the rifle strap and retreat, but I grabbed a snake each time. 

Ten instructors were standing around me and watching me. Why are they watching me while I'm cleaning my weapon in a snake's nest? Why did they let us set up the patrol base here? Didn't they see how many snakes there are?

Luka realizes he is standing in snakes nest

I shook my head. This isn't real, I'm hallucinating … Concentrate, Zoki! You are here, the snakes aren't real! I closed my eyes, breathed, and opened them again. I was in the dark, there were no snakes anywhere and no instructors.

I didn’t tell anyone about the snakes. I was ashamed that I wasn’t good enough for this unit because I was already seeing things. Even later, during security, I thought about it for long minutes at a time. It at least kept me awake so I didn’t fall on my face.

We completed the priorities two hours before the planned move forward. During resting, we had first intended to switch every 30 minutes. We quickly figured that wouldn’t work. We reduced the time first to 20 and then to 10 minutes.

“Come on, wake up, it's your turn!”

“No, it's not, it's somebody else's!” I muttered.

“It's yours!”

“Oh, okay. I'm on security!”

I jumped from the sleeping position to the kneeling guard position. I looked at a colleague who was already snoring. He was shaking.

“Come on, cover yourself, you’re shaking like a leaf!”

Team is already sleeping

He didn't hear me. I left the guarding position and covered him with a military poncho. He kept on sleeping as peacefully as a child. I counted down the minutes and then seconds until the end of my shift. Then I just rolled back into a supine position.

I slept a full 60 minutes that night. This was the amount of officially planned sleep, and we all probably added a minute or so of involuntary sleep while standing on guard ... It's difficult to fight against the body.

I was glad to start moving again. I wasn't as cold while moving and was also a little less sleepy. In addition, I was able to ignore the worries that I was already fading away and starting to become crazy.

We put everything away and moved on. That’s when I noticed Recta had a different weapon on him. Instead of the original support weapon, he was carrying a huge thing with a scope and belt on his side.

“Hey, Shrek, what's with Recta?” I asked.

“He fell asleep during security, so the instructors confiscated his weapon.”

Well, Recta at least had a fictional weapon. In Old Man's case, the instructor took the upper part of his rifle so that only the plastic part was left in his hand. We had to do quite a number of rewards for him to get the second part of the rifle back as well. The automation of the push-ups turned into falling to the ground. We couldn't be more dirty or sweaty, there was only room for us to maybe smell a bit worse.

The sun was high up in the sky. In daylight, many things seemed a little easier. All of a sudden, I found myself in a huge cathedral. Enormous Ionic pillars towered left and right, and I was walking between them. 

Luka is seeing cathedral

Breathe, this is not reality! I reminded myself. I took a closer look at the pillars and saw that they were just tall trees and shrubs. I kept on walking. Here and there, a pillar still appeared between the trees.

The pain in my knee was increasing while walking. The swelling was already so big that the pants around my thighs were quite taut. I set myself on autopilot again and thought only of the task they had assigned to us in the morning.

We helped each other all the time. This help included, above all, making sure that everyone was doing their job and not falling asleep.

The instructors were constantly monitoring us and yelling.

“What are you dragging yourselves like that for?! Feeling sorry for yourselves? It's your own fault that you're so incompetent!”

Nothing was ever good enough, but we kept dragging ourselves on! We kept falling and picking each other up because our bodies were no longer holding us. We were trying our best, but it was slowly becoming obvious that even that wasn't good enough.

“Contact at 12!”

The physiology behind the madness

In layman's terms there is an explanation behind the snakes. But first let's discuss why an alcoholic is having delirium tremens after they are going cold turkey on the alcohol.  

Alcohol blocks your REM sleep, but REM is essential for mental health. Delirium tremens is a rapid onset of confusion usually caused by withdrawal from alcohol.

Alcohol stops you from dreaming (most dreams occur in the REM stage), which deprives you of healthy, restorative sleep. When you end the years of abusing alcohol by going “cold turkey” (meaning, you completely stop drinking), you regain your ability to dream since the alcohol is no longer blocking you from healthy, natural sleep.

You get served all your dreams storming in with that confusion, shaking, fever, hallucinations… That nightcap you take so you can sleep easily is actually not good for your sleep. 

Now that we know one of the many reasons why sleep and dreams are important, why do we hallucinate when we do not sleep? Well, our body will get its medicinal amount of dreams whether we are asleep or awake.

All the dreams come rushing in while we are up and about. During deep sleep our brains (to put it in layman's terms) cleans up our system. This is vital for our longevity. Talking about more closely related effects on us. 

Sleep deprivation stages

After only 16 hours of being weakened, our mental status starts to decline. After 20 hours of wakefulness, it's like having a couple of beers in us. After 24 hours we are already a bit cognitively impaired. 

After 36 hours you will have trouble remembering what you are doing, remembering names and people. If you’re deprived of sleep for 48 hours, your cognitive abilities worsen, adding even more to previous problems. Your body tries to switch over to a backup system, going into brief periods of microsleep lasting 30 to 60 seconds, which help preserve some functions. People drift out of it, not knowing they were sleeping. They think they are only deep thinking, when they wake you up. You immediately say, “I wasn't sleeping!”  

After 72 hours without sleep, you should expect to experience hallucinations, visual illusions, an inability to concentrate, and immediately forgetting small tasks. 

Ninety-six hours of sleep deprivation. You are unable to interpret reality. You close your eyes knowing things aren't there. Opening them again, the hallucinations are still there. You can talk to the hallucinations, and maybe “give” them food and drink (although most of the time you’re giving food and drink to a tree, but it's a good effort). 

Sleep deprivation is made worse from malnutrition, dehydration, and heavy load-bearing. You aren't crazy when you are hallucinating. You are just becoming crazy. Besides the mental effect, your whole body is under attack and experiencing some kind of medical difficulties. You need healthy, restorative sleep as soon as possible. 

Get Luka's Lynx Book

Get the digital edition of Luka's book here: Lynx: Story of a former special operations medic

Lynx Book

Combat Medic Luka Zorenc

About the author:

Luka Zorenc

Born and raised in Ljubljana, Slovenia. Former veterinarian technician now a medic in Special operations forces. A lifelong student, trying to help people and have fun in the process.

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Published: 07-08-2021