Why Sleep Is the Most Underrated Tool for Good Health, Longevity, and Productivity

11 min readNov 29, 2020

“Men who sleep five hours a night have significantly smaller testicles than men who sleep eight hours or more”

This is how Professor of Neuroscience and Psychology at the University of California, Matthew Walker kicked off his speech to employees at Google.

I was wrapped up in a blanket, sipping my honey and camomile tea on a long-overdue Sofa-Sunday, when I decided to watch a YouTube video that my sister had sent in our family WhatsApp group. With it, she had written what I assumed to be an exaggerated instruction: “IF THERE’S ONE THING YOU WATCH IN YOUR LIFE, LET IT BE THIS”.

In hindsight, it was no exaggeration. I was gripped to the screen from the very first minute of the video. I was shocked to realize how little we know about the importance of sleep. Sure, we all know it’s a human necessity, just like food, water, oxygen…but getting a full 8 hours of sleep is something that an alarming number of us consider a luxury as opposed to a necessity.

According to The National Sleep Foundation, adults between the ages of 18 and 64 need to sleep between 7 and 9 hours every night; once we fall below the 7 hours of sleep, the health implications become significant. And yet, whilst 84% of Americans were getting at least seven hours of sleep per night in 1942, this figure how now dropped to 59%.

Alarmingly, 40% of Americans are only getting six hours or less of sleep per night.

Matthew Walker convinced me that this is one of the biggest public health challenges of the 21st century. We’re suffering from a silent sleep epidemic that isn’t on most people’s radars. We’ve become so obsessed with productivity that sleeping eight hours a day almost carries the stigma that we’re lazy. It’s a mistaken belief, and it’s also pretty ironic. Sleep-deprivation has huge implications when it comes to processing and storing information; it also has huge health implications, it affects our mood, and it even alters our DNA.

Here’s what I learned from his speech, followed by some tips on how you can improve the quality and the quantity of your sleep.

Impact on Memory & Learning

I used to sleep no more than 5 or 6 hours per night during exam season at university. And I was on the generous side of the spectrum; a lot of my friends pulled all-nighters the night before an exam. I remember meeting up to revise together in the evenings, and reading my notes in bed…little did we know that we were actually doing ourselves a massive disservice.

Getting a decent sleep is just as important before we learn new information as it is after we learn new information. Think of your brain like a sponge; sleep essentially drains your brain so that it doesn’t become waterlogged, and leaves space to absorb new information. Once you absorb that new information, sleeping helps to transfer that information from the hippocampus, which is essentially your brain’s inbox, to the long-term reservoir in your brain; the cortex.

Before Sleep

Walker describes an experiment conducted on two groups of healthy adults who were subjected to two different conditions. The “sleep group” got a full eight hours of sleep. The “deprivation group” was kept awake without any caffeine or naps. The following day, the scientists took MRI scans of their brains whilst these two groups learned a list of new facts. Lo and behold, the sleep group performed much better. They found that there was a 40% deficit in the ability of the brain to make new memory without sleep…that’s the difference between acing an exam and failing it.

The scientists observed healthy learning activity occurring in the brains of those adults who had received eight hours of sleep. In contrast, they saw no significant signals coming from the hippocampus of those individuals in the sleep-deprived group; it was as though their inboxes were full and they couldn’t receive any more information.

After Sleep

Storing this new information after we’ve learned it is likewise very important. By recording sleep with electrodes placed all over the head, Walker and his team discovered that there are powerful brain waves that happen during the very deep stages of sleep, on which they could see bursts of electrical activity occurring. The combined effect of these waves and bursts act as a transfer mechanism, that takes the new information in your inbox (the hippocampus) into a safe haven in your brain for long-term storage (cortex). This system helps you retain information for longer, and frees up space in your inbox so that you can start the learning process anew.

Medical Implications

It probably won’t come as a surprise to you that as we get older, our memory deteriorates. And likewise, so does the quality of our sleep. These two factors are significantly interrelated; in fact, the disruption of sleep may just be an underappreciated factor that is contributing to the cognitive decline in aging and in Alzheimer’s disease.

The trouble is, a large proportion of elderly people, and an increasing ratio of the population at large is consuming sleeping pills. They may think this is improving their sleep, but actually, Walker explains that these pills are merely sedatives. Just like alcohol, they essentially knock you out. They may help you fall asleep faster, but you’re not getting the natural sleep that you need for that essential transfer of information between your hippocampus and your cortex to occur.

This may sound somewhat masochistic, but a potential solution is currently in the making; it’s called direct current brain stimulation. It involves applying electrodes to the head and inserting a small amount of voltage into the brain, which serves to amplify the size of the deep-sleep brain waves. You can almost double the memory benefit you’re getting from sleep.

Social Implications

You probably guessed that the implications in the arena of education are huge; a school in Edina, Minnesota is living proof.

The school changed its start time from 7:25 am to 8:30 am and saw a 212-point increase in the average SAT scores of their top-performing students.

They focused on the top 10% performing students; those for which there was theoretically less room for improvement, and saw the average SATs core go from 1288 to 1500. This can make the difference in the university that these students go to, and potentially change their life trajectory!

Additionally, studies reveal that the life expectancy of students increases when they’re given more time to sleep! When a school in Teton Wyoming changed its start time from 7:35 am to 8:55 am, they measured a 70% reduction in car crashes amongst students aged 16 and 18 years old! To give you a little context; anti-lock braking systems reduce accident rates by 20–25% and they were considered revolutionary. Here we have a biological factor that can drop accident rates by 70%!

Impact on Emotional & Mental Health

Iwas glad to hear that I’m no anomaly when it comes to being an irrational witch when I’m feeling sleep deprived. Much to the alarm of anyone around me, I can go from expressing anger to crying, to laughing in about a minute. I could be watching an episode of Modern Family, it really doesn’t matter. If I’m feeling sleepy and I can’t get to sleep, I’m a ticking time bomb.

And this is exactly what a student, under the pseudonym of Jeff, was like in the play-back of a science experience Walker’s team conducted. He was made to stay awake overnight, much like many students would the night before an exam. He kicks off the night looking chirpy and optimistic…a few hours into sleep-deprivation he’s asked how he’s doing, and within the space of about one minute, he goes from expressing total anger to being relaxed. I feel you Jeff.

It turns out that the Amygdala, the part of our brain that controls emotions, is 60% more reactive when we’re sleep-deprived.

And what’s probably more worrying is that this neurological pattern is similar to that in people who suffer from psychiatric conditions such as schizophrenia and depression. In fact, Walker couldn’t point to a single psychiatric condition in which sleep is normal.

Impact on Health & Immune System

During his speech, Walker shares images from an experiment conducted by researcher David Gozal at the University of Chicago, which revealed a 200% increase in the speed and the size of cancerous growth growing on a mouse whose sleep had been interrupted every night for one month. In those mice that slept normally, the growths grew only slightly.

What’s more alarming perhaps is that cancer in those mice that were sleep-deprived had metastasized; they had invaded other vital organs.

The reason for this is that restricted sleep hinders our killer cells’ ability to identify dangerous foreign elements and eliminate them. It turns out that our bodies make cancer cells every single day! It’s these ‘killer cells’ that destroy them before they become malignant masses. And after just one night of restricted sleep, where you only get 4 hours of sleep, you experience a 70% drop in killer cell activity…Imagine the state of your immune system after one week of sleep deprivation.

A lot of people feel uncomfortable about the idea of genetically modifying embryos or food — but it turns out that by not getting the hours of sleep that we need every night, we’re performing this experiment on ourselves! Walker talks of an experiment that involved limiting a group of healthy adults to sleep for only 6 hours a night for a week to see whether there were any alterations to their genetic codes. The experiment showed that 711 genes were distorted by a lack of sleep, and these were the genes related to the promotion of tumors, chronic inflammation, stress, and cardiovascular disease.

Our bodies are extremely fragile to even the slightest sleep perturbations. Take the effect of daylight-savings time as an example; a global experiment that applies to 1.6 billion people across 70 countries twice a year. In the spring, when we lose one hour of sleep, there is a 24% increase in the number of heart-attacks. In the fall, when we gain one hour of sleep, we see a 21% decrease in the number of heart attacks.

Sleep is so important that the WHO now classifies any form of night-time shift work as a probable carcinogen. Not only can sleep deprivation shorten our lives, but the quality of our lives will also be worse when we don’t get the sleep that we need. I’m sure that you, like I want to have the best quality of life possible. So here is some of Walker’s best advice on how you can improve your quantity and quality of sleep.

Tips for catching better Zs

1) Be consistent

It’s super important to build a regular sleeping pattern, i.e. going to bed at the same time every day and waking up at the same time every day. One thing that helps me do this is to set an alarm at the same time every morning (like most people do), but also to set an alarm in the evening; two in fact.

My first alarm goes off at 10:00 pm, at which point I start getting ready for bed; take a shower, brush my teeth, put on pajamas…whatever it is. Then my second alarm goes off at 10:30 pm, at which point I get into bed and read until I fall asleep.

2) Reduce your exposure to light

We need darkness in the evenings for our bodies to release melatonin, the hormone that helps induce sleep.

Not everyone has ceiling lights that you can just dim down; if you do — use them. If you don’t, try buying a table lamp or a standing lamp that you can switch on in the corner of the room instead of having your ceiling lights on. It goes without saying that blue light from our electronic devices (TVs, Phones, Tablets…) should be avoided. Try leaving your phone in another room; if you’re relying on it for your alarm, consider buying an alarm clock.

3) Keep the room cool

It turns out that our brain and body temperature needs to drop by 2–3 degrees to find good sleep. Our bedrooms should be at around 68 degrees Fahrenheit, or 18.5 degrees Celsius.

4) Avoid alcohol and caffeine

I actually always thought that a glass of wine in the evening helped me sleep. I’m a pretty bad sleeper, and drinking a glass of wine makes me doze off quicker than usual. But it turns out that both alcohol and caffeine hinder our ability to go into a deep sleep; the type that we need for those short-term memories to be converted into long-term memories.

The result? We wake up the next morning not feeling refreshed. Although we may not realize that our sleep has been more fragmented than usual, we haven’t really rested as well as we need to.

5) Don’t stay in bed awake

It helps our brain to associate being in bed with sleeping. If we stay in bed when we can’t sleep, or we wake up in the night, or we’re having a lazy Sunday, our brain starts to lose this connection. A good way to keep this association going is to get out of bed and read in dim lighting in another room. Don’t reach out to check your phone!

Another good way is to meditate; it’s been demonstrated to relax the body. One thing that works for me, and I have no scientific explanation for this, is to meditate in bed without a pillow. There’s something about lying completely flat on my back that I find relaxing — maybe it reminds me of yoga? Who knows? The important thing is to make your own associations; find what works for you.

My Five Minute Journal arrived in the post a couple of weeks ago. Almost every night so far in the “what two things could have improved your day today” section, I’ve written the words “more sleep.”

Because sleep isn’t a luxury; it’s a fundamental human necessity, that has fallen under our radar for far too long.