Transcription
Before reading the book Why We Sleep, I believed that sleep is non-productive activity that we naturally do. But I was wrong. Sleep is the single most productive thing that you can do during the day.
In this video, I will explain the wonderful things that happen when you get enough sleep and the alarmingly bad things that happen when you don't, both for your brain and for your body. It is proven that men who routinely sleep just 4 to 5 hours a night have a level of testosterone that is that of someone 10 years their senior. An equivalent amount of impairments happen in female reproductive health as well.
Now let's look at the brain and the process of learning and memory. It was already scientifically confirmed that you need sleep after learning to hit the save button on those new memories so that you don't forget. But recently it has been confirmed that you also need to sleep before learning in order to prepare your brain. When you sleep before learning, your brain becomes like a dry sponge ready to soak up new information. And without sleep, the memory circuits of the brain become blocked and you can't absorb new memories.
To prove this hypothesis, the author took a group of individuals and divided them into two groups, a sleep group and a sleep deprivation group. The sleep group got a full 8 hours of sleep, but the deprivation group was kept awake under supervision. And then they asked both groups to learn a list of new facts and the result was significantly different. The sleep deprivation group scored 40% less compared to the sleep group. To put this in context, 40% is the difference between getting an A and failing miserably on the exam.
There is a structure that sits on the left and the right side of your brain called the hippocampus. And you can think of the hippocampus almost like the informational inbox of your brain. It's very good at receiving new memory files and then holding on to them. And when you look at this structure in those people who had a full night of sleep, we see lots of healthy learning related activity. Yet in those people who were sleep deprived, activity level was very low. So it's almost as though sleep deprivation had shut down your memory inbox and any new incoming files were just being bounced back.
Sleep is also essential for your body. Let me tell you about sleep loss and your cardiovascular system and you will see how even 1 hour lack of sleep makes a huge difference. There is a global experiment performed on 1.6 billion people across 70 countries twice a year and it's called daylight saving time. Now in the spring when we lose 1 hour of sleep, we see a subsequent 24% increase in heart attacks that following day. In the autumn, when we gain an hour of sleep, we see a 21% reduction in heart attacks. Isn't that incredible? And you see the same things for car crashes, road traffic accidents, even suicide rates.
Now, I want to focus on sleep loss and your immune system. In your body, there are cells that protect your immune system against attacks. They operate as secret service agents and protect your immunity. They are very good at identifying dangerous elements and eliminating them. If you restrict your sleep and only have 4 hours of sleep for one single night, you will see a 70% drop in cell activity that is protecting your immune system. That's a concerning state of immune deficiency.
There is a significant amount of links between short sleep duration and your risk for the development of numerous forms of cancer. In fact, the link between a lack of sleep and cancer is now so strong that the World Health Organization has classified any form of nighttime shift work as a probable carcinogen. You may have heard of that old saying, "You can sleep when you're dead." Well, it is completely unwise advice. There's a simple truth. The shorter you sleep, the shorter your life.
If increasing your risk for the development of cancer and Alzheimer's disease are not scary enough for you, then let's hear this one. Lack of sleep will even destroy your biological life itself, your DNA genetic code. In one study, they took a group of healthy adults and limited them to 6 hours of sleep a night for 1 week. And then they measured the change in their gene activity profile. And there were two critical findings. First, a sizable and significant 711 genes were distorted in their activity caused by a lack of sleep. The second result was that about half of those genes were increased in their activity. The other half were decreased. Those genes that were switched off by a lack of sleep were genes associated with your immune system. In contrast, those genes that were increased were genes associated with the promotion of tumors, stress, and cardiovascular disease.
There is simply no aspect of your wellness that can escape from sleep deprivation. It is like a broken water pipe in your home. Sleep loss will leak down into every part of your physiology, even your DNA.
At this point, you may be thinking, "Oh my goodness, how do I start to get better sleep? What are the tips for good sleep?" I have two pieces of advice from the book. The first piece of advice is to keep it cool. Your body needs to drop its core temperature by about 1° C to initiate sleep and then to stay asleep. It's the reason you will always find it easier to fall asleep in a room that's too cold than too hot. So, aim for a bedroom temperature around 18° C. Having a hot bath before bed is also a great way to drop body temperature and sleep fast.
You might also be wondering to know what to do if you go to bed but can't fall asleep. I'm sure you know that feeling of tossing around in your bed for an hour but not being able to fall asleep. So, if you're staying in bed awake for more than 20 minutes, you should get out of bed and go to a different room and do something different. The reason is that your brain will very quickly associate your bedroom with the place of wakefulness. And you need to break that association. To explain it differently, you'd never sit at a dinner table waiting to get hungry. So, why would you lie in bed waiting to get sleepy?
The second advice is regularity. Go to bed at the same time, wake up at the same time, no matter whether it's the weekday or the weekend. Regularity is king and it will anchor your sleep and improve the quantity and the quality of that sleep. One more thing, never snooze. Snoozing is a very stressful event for your cardiovascular system. There's a strong spike in stress chemicals when you hear the alarm and if you keep snoozing that it impacts you in a very bad way. This might seem a very small impact but can you imagine its effects if you keep snoozing every day, every week, every month, every year. It is good to use the alarm, but try to get up from the first time.
Many of us snooze a lot because we go to bed late and don't get enough sleep. So, why not put an alarm for going to bed, not just for waking up? For example, if you're going to bed at 11:00, you can put an alarm for 10:45 and use those 15 minutes to prepare for bed.
Let's say you go to bed at 11 and wake up at 6:00 a.m. How would you know if this is enough for you and you had enough sleep? How would you know that you are not sleep deprived? The tricky thing about sleep deprivation is that when you are sleep deprived, you don't know that you are sleep deprived. Have you seen a drunk person who can't walk a straight line but keeps saying that he's not drunk? Well, sleep deprivation works in a similar way. Two signs to look for in order to know if you've had enough sleep or not. First, when you wake up in the morning, check if you can operate without coffee. Second, around 12:00 or 1:00 in the afternoon, check yourself to see if you need a nap or not. If you can continue without a nap or without being tired, then it's a sign that you had enough sleep.
Sleep, unfortunately, is not an optional lifestyle luxury. Sleep is a non-negotiable biological necessity. It's your life support system. And the increase of sleep deprivation throughout industrialized nations is having a catastrophic impact on our health, our wellness, even the safety and the education of our children. It's a silent sleep loss epidemic and it's fast becoming one of the greatest public health challenges that we face in the 21st century. It is now time for us to reclaim our right to a full night of sleep without embarrassment or that unfortunate stigma of laziness.
Sleep does not operate as a bank. You can't accumulate a debt and then hope to pay it off at a later point in time. You can't work a lot during the week and recover from it by sleeping longer during weekends. The reason sleep deprivation has a catastrophic effect and our health deteriorates so quickly is because mother nature throughout the course of evolution has never had to face the challenge of this thing called sleep deprivation. So she's never developed a safety system against sleep deprivation. And that's why when you undersleep, things just sort of implode so quickly both within the brain and the body.
Humans are the only species that sleep deprive themselves. You can't see other species doing similar things. That is why our body and brain have no protection system against sleep deprivation. And you must prioritize sleep. There is no other way around.