Transcript of How Sleep Boosts Focus, Memory & Performance: Sofia van Buuren

Read the full transcript of biohacking entrepreneur Sofia van Buuren’s talk titled “How Sleep Boosts Focus, Memory & Performance” at TEDxErasmusUniversityCollege (June, 2 2025).

Listen to the audio version here:

The Pressure We All Feel

Sofia van Buuren: Pressure. Do you feel it? From friends, from work, from university, from chores, from gym, from taxes? It’s also overwhelming. University pressure creates an environment where performance is paramount, often at the detriment of our health, particularly our sleep.

This is something I experienced firsthand a couple years ago. I remember it distinctly. It was midnight. I was cramming for tomorrow’s exam, fueled by coffee and sheer determination, but midnight turned to 2 a.m., turned to 4 a.m., and suddenly, I realized that I wasn’t sleeping. “I’ll sleep later,” I told myself, but the next day, when I got to the exam, I rubbed my eyes, but my mind blanked. I couldn’t remember a single thing, and the hours of study suddenly felt wasted.

Actually, losing a night of sleep can reduce your ability to learn by up to 40%. That’s like losing half of your sleep time and half of your study time. Losing that one night of sleep made me feel so cognitively impaired, but it motivated me to try to change my sleep habits, and in turn, I eventually learned how to sleep better, and now, I feel almost superhuman.

So today, I’m going to show you how I did that. I’m going to teach you how sleep is not just a chore that you have to fit into your schedule, but an active tool that you can use to improve your memory, your focus, your learning, and your creativity. Drawing from neuroscience, we are going to look at science-backed strategies to help you optimize your sleep, and thus, your productivity.

Your Brain’s Overnight Pit Crew

Think of sleep like your brain’s overnight pit crew.

It’s divided into four different stages, or crew members, and they cycle through the night in 90-minute rhythms. The first crew member is Dave the dial-turner. Dave turns down the dial of the consciousness of your mind, tending you into sleep. Second, there’s Linda the librarian. She sorts information from your short-term memory to your long-term memory. Third, there’s James the janitor. James sweeps away all the toxic byproducts that you built up throughout the day. Fourth, and finally, there’s Frank the film director. Frank directs the dream movies that you see at night when you sleep.

Think of them like a relay race, handing off duties from one to the next person, and that way, they cycle throughout the night. Now, I’m going to talk about each of the stages in depth, so that we can learn their mechanisms and their responsibilities, and the tips that we can use in order to help them do their responsibilities, and thus, be more productive.

Stage 1: Dave the Dial-Turner – Transitioning Into Sleep

Now first, we have the transition into sleep. Dave the dial-turner comes in. This stage of sleep lasts about seven minutes, and it only has to happen once. Dave turns down the dial of the consciousness of your mind, settling your neurons. He also turns down the dial of the external volume, making the world around you fade away, and sending you into sleep.

But, as I’m sure you’ve all experienced, this doesn’t always go according to plan. Sometimes your brain just won’t shut off, like a radio with external noise that you just can’t turn off. There’s so much pressure going on, and so many thoughts trailing from all the work, uni chores, and it just won’t turn off. It’s so frustrating, but there are things that we can do to change this.

Dave’s ability to turn the dial is greatly influenced by light. I’m going to tell you three types of light, and how they impact your sleep, and what we can do to optimize them.

ALSO READ: Examining Depression Through The Lens of The Brain: Dr. Helen Mayberg (Transcript)

The Three Types of Light That Control Your Sleep

Number one is morning sunlight. The position of the Sun in the sky tells your body what time of day it is, and viewing morning sunlight tells your body that it’s morning, and it tells you to secrete the wake-up hormone, cortisol. Cortisol tells your body that it’s time to wake up. It tells it to get going and energized for the day. Getting 10 minutes of morning sunlight exposure helps reset your body to wake up naturally at that same time every day.

The second type of light is blue light. Think from screens, phones, TVs, laptops, things like that. Unfortunately, your brain gets confused when it sees blue light. It thinks that it’s daylight, and it thinks that it’s daytime, and what happens then is that it again secretes the cortisol hormone to wake you up. And then we don’t want this when we’re going to bed, right? So this is why it’s incredibly important not to view screens an hour and a half before you go to bed.

The third type of light is red light. Red light does the opposite. Red light helps you secrete melatonin. Melatonin is the sleep hormone. Melatonin makes you feel tired and makes you want to fall asleep. Now, doing red light sounds kind of difficult. Naturally, this happened in caveman times when we viewed a sunset, but nowadays we can also induce this artificially. In my house, actually, when it’s time to go to bed, I turn all the lights down to a medium kind of red light and our glasses with a red lens so that only red light can penetrate my eyes. This makes the transition into sleep incredibly quick and easy.

By optimizing your morning and evening routines, not only can you fall asleep quicker, but you also wake up with much more energy. This saves you a lot of time because you’re not tossing and turning for an hour trying to fall asleep, and you wake up productive and ready to go.

Stage 2: Linda the Librarian – Memory Consolidation

Now, we’re going to move on to the second stage of sleep, light sleep. Imagine your brain turns into a vast library, books and shelves everywhere. Linda, the librarian, comes in, and just like a regular librarian shelves incoming book shipments to their proper spots in their permanent shelves, Linda shelves memories from your short-term memory into your long-term memory. So, essentially, she’s responsible for making memories permanent.

Linda works the hardest of all the four crew members. She lasts a whopping 50% of your total sleep time. So, this is a large chunk, but what happens if we cut her time short by, say, cramming late for an exam the next day or working on a project really late? Linda falls behind. She doesn’t have enough time to put the memories from your short-term to your long-term memory, and thus, you might forget things. Memories will stay in your short-term, and they’re easily forgotten.

Some things hinder Linda. Late-night eating delays melatonin production, and late-night exercise increases your core body temperature. Both things make it incredibly difficult to fall asleep, and thus, decrease your total sleep time.

But other things can help Linda. My absolute favorite sleep tip that I’ve personally noticed the biggest benefit from is going to bed and waking up at the same time every day. Similar to light, this helps your body predict what time of day it is, and thus, what hormones to secrete when, and it makes it easier to fall asleep and wake up. Everybody needs a different amount of sleep, but a general rule of thumb is at least eight hours.

ALSO READ: Transcript of Improving Our Neuroplasticity: Dr. Kelly Lambert

One study of American high schools found something interesting when they delayed their start times by one hour. They found that way more students were getting the required eight hours of sleep, but more importantly, something else happened. They noticed an incredible increase in attendance, GPA, and standardized test scores, all because the students were sleeping more, and thus, remembering more.

Stage 3: James the Janitor – Deep Sleep Detox

Now, let’s move on to stage three. Stage three is deep sleep. This is where James the janitor comes in. James sweeps away all the toxic byproducts that you accumulated throughout the day, but if James doesn’t have the right environment or enough time to remove all these toxins, they build up, and they clog your neural pathways. What can happen from this is that you have a hard time recalling information. Stress can feel so overwhelming, and it can actually be implicated with diseases, like Alzheimer’s.

Luckily, there are some things we can do to help out James. James likes to work in a cool environment, specifically 18 degrees Celsius. He likes this because it helps him to get his job done. Keeping our bedrooms cool, specifically 18 degrees, helps our muscles relax, and helps our neurons settle. This allows us to fall more easily and stay more easily in deep sleep, and thus, help James do his job.

Unfortunately, some things also hinder James. I’m sure you’ve probably heard or experienced yourselves that alcohol and cannabis can help you fall asleep, and sure, they definitely make you feel sleepy, but in reality, they’re messing with your sleep. Alcohol and cannabis make it incredibly difficult for the crew members to do their jobs correctly and execute on time. So although you might think you might…

All right, now fourth and finally, we have the fourth stage of sleep, REM sleep. I’m sure you’ve all heard of REM sleep, or rapid eye movement sleep. Imagine your brain turns into a giant movie studio. Frank the film director takes over. He’s in charge of making the dream movies that you see when you sleep. But your body does something really weird during REM sleep. Usually, the emotional part of your brain and the rational part of your brain are highly connected. But during sleep, they’re disconnected. They’re divorced. This does something special. It allows your brain to separate emotions from memories, and thus helps you with emotional regulation.

Think back to the last time that you were kind of upset about something. Maybe your co-worker did something kind of annoying. They sent you an email that they really didn’t need to, and you were kind of frustrated about it, right? But then you went to bed, and you woke up the next day, and it didn’t really bother you anymore. This is the power of REM sleep. Your body is able to separate emotions from memories. It’s actually where the idea to sleep on a problem comes from.

But the bulk of REM sleep occurs really late at night, so in the early morning. And this poses a problem, because let’s say we cut our sleep short to work on a project really late at night, or like I was, studying for an exam. Then the REM sleep is also cut short. This leaves us highly emotionally reactive the next day. This makes stress feel overwhelming, leads us to be prone to risky behavior, and makes us really poor at problem-solving and decision-making. Think of a little whiny toddler who missed his nap. That’s kind of what we turn into, actually.

ALSO READ: Taking on Obesity: Holly Wyatt at TEDxMileHigh (Full Transcript)

One study done by the American Association of Drug and Alcohol Abuse, they did a study on cocaine addicts, specifically recovering cocaine addicts. And they tried to figure out what caused them to relapse. Well, what they found was a really strong indicator of relapse, and that was a lack of sleep. And that’s because with a lack of sleep comes a lack of REM sleep, and that’s inability to make good decisions.

Now, one more thing also happens during REM sleep. Your brain also is able to do something it’s not normally able to do. During REM sleep, your brain is able to make connections between things it normally wouldn’t think of as connected. This is the essence of creativity and creative problem-solving.

How to Boost REM Sleep

Now, this is all good and well, but how can we increase REM sleep? How can we help it out, right? Well, since REM sleep occurs mostly in the early morning, we can help it out by increasing our sleep in the morning. So essentially, by adding on 25 minutes to your sleep in the early morning, you can boost REM, and thus boost your decision-making, boost your creativity, and, yeah, be more productive.

Creating the Perfect Sleep Environment

Now, ideally, we would want to create an environment that makes it incredibly easy for each crew member to do their job. We make Dave incredibly quick at turning the dials down on your consciousness, so you fall asleep more quickly. Linda is able to have enough time that she needs to put the information from your short-term to your long-term memory. James, the janitor, has the proper environment that he needs to sweep out all of the neurotoxins, so you’re physically capable. And Frank, the film director, has all the time he needs to separate emotions from memories and boost your creativity.

Now, all of the habits I’ve shared with you today are useful in not just one, but multiple stages. And this is important, because every stage has a purpose. Every habit has an impact. And the good news is that small changes can make a big difference.

The Power of Prioritizing Sleep

Let’s look back to that anecdote that I shared with you earlier. But think about how you would act differently if you were me now that you’ve heard this talk. Instead of staying up late like I was till, like, 4 a.m. studying, you prioritized your sleep. You got your full 8 hours. The next day, you get to the exam, and Linda has stored all the memories, so the information froze freely. You slept really well. You’re physically capable from James. And Frank, the film director, is able to make you really creative at problem-solving. You open the test booklet the next day, and the information just flows freely. It’s seamless.

Conclusion

So, tonight, as you prepare for bed, think about which of these strategies that you can use to help improve your sleep. Because improving your sleep doesn’t just mean waking up well-rested. It means waking up smarter, sharper, almost superhuman, ready to take on the world. Make the ordinary act of sleep your extraordinary advantage. Thank you.