But I think it's more important to save your sleep than your bill.
I'm Masashi Yanagisawa, a sleep researcher.
Are you sleeping well?
Today I'm here to answer your questions on sleep.
This is Suimin (sleep) Support.
A question from Kana.
"Is there a difference when you sleep properly prepared
and when falling asleep unknowingly?"
Yes, there is.
Falling asleep unknowingly means
you didn't arrange your sleeping environment.
This tends to degrade sleep quality.
Don't sleep where it is noisy or brightly lit.
Make sure to lay down flat.
Always get yourself ready for bed.
Next is from Nogizaka Horo.
"Does laying down with closed eye have similar effect as actual sleep?"
No, it does not.
Your desires for sleep will never be fulfilled until you sleep.
Of course, laying down would ease your body,
but it won't alleviate your sleep deprivation.
Next is from Go-chinjin.
"Is it true that sleep brings up a child well?"
Yes, it is.
The key role of growth hormones is
to regulate growth in children, as the name indicates.
These hormones are
known to be secreted most when you are in your deepest sleep.
Specifically, during non-REM sleep.
Getting sufficient sleep leads to
excretion of growth hormones, promoting growth in children.
But for adults, not getting enough sleep leads to their growth.
Constant lack of sleep will
surely add on more weight to your body and increase health risks.
Poor sleep will inhibit your efforts to lose weight.
Kyo-su asks,
"Is too much sleep bad for you?"
A common misunderstanding.
You probably often see data that show
people who sleep 7 hours a day are most healthy.
And the death rate is high for those who get too little or too much sleep.
Similar results are reported all around the world.
But it is not well known that the cause and effect are
the other way around.
Too little sleep simply means you're lacking sleep, which is bad for you.
On the other hand, note that people can't "sleep too much."
Let's say you are getting enough sleep.
You won't be able to sleep longer than your body needs.
So, if you are sleeping 9 or 10 hours a day,
there's probably something wrong with your body or your brain.
Or suffering from sleep apnea.
In other words, you either have poor health or a sleeping disorder.
That's why you're sleeping a lot.
You don't get sick from too much sleep. You sleep too much because you're sick.
"Sleeping too much" is the effect, not the cause of poor health.
Radion's question.
"Does bedding affect our sleep?"
Comfortable bedding is very important.
Even in the summer, make sure that you cover yourself with something.
It can be a very light blanket.
Because even while we're sleeping, we're regulating our temperature.
If we feel hot, we release heat by uncovering our arms and legs.
If we feel cold, we pull the covers over ourselves subconsciously.
But if we don't have any blanket, then we have no choice.
Some people don't like using blankets.
If so, then your room is too hot.
I recommend keeping the air conditioner on all throughout the night.
Some might worry about the electricity bill.
But I think it's more important to save your sleep than your bill.
Next question is from Reaf M.
"People say golden hours start from 10 pm.
When we get home late, is it better to sleep immediately
or to take a hot bath and then go to sleep?"
First and foremost, the golden hours of sleep
does not necessarily start from 10 pm.
The timeframe varies among people.
If you're a night owl,
your golden hours start later than the early birds.
You may have also heard that the first 2 hours after going to bed,
when you're in your deepest sleep, is the most important timeframe.
Indeed, the first deepest sleep comes in the first few hours.
Later on, you start to enter your REM sleep phase,
and this phase is just as important.
It's critical to your body and brain.
So basically the entire night are the golden hours.
With that said, if you get home late,
it's better to keep to your bedtime schedule.
Consider skipping the bath and taking a morning shower.
The important thing is to try to keep your regular sleep routines.
Taking a bath does have a positive effect on sleep quality.
The key points are
to take the bath an hour to 1.5 hours prior to your bedtime,
and to soak yourself in the bath.
You sleep better when you first raise and then lower your body temperature.
But when it's closer to your bedtime, this routine becomes meaningless.
So, if you come home later than usual, it's better to go to bed immediately.
From Kometaro.
"What's most effective for sleep quality?"
I'd like to emphasize that the most important is amount of sleep.
Make sure you allocate time for sleep.
It's silly to worry about quality if you're not getting any.
That's the first point.
The next point is
there isn't any universal method which enhances the quality of sleep.
Sleep is all about subtraction.
It's about removing factors that are known to
degrade the quality of sleep.
For example, don't drink caffeinated beverages in the evening.
Or drink any alcohol after dinner.
Another factor is your bedroom.
Keep it dark and quiet with regulated room temperature.
The third point is to recognize the quality of your sleep.
That is, try visualization of your sleep quality.
So, what you do is,
you measure your brain waves.
You can do that by attaching these thin electrodes on your head
before going to sleep.
"Start measuring your brain waves. Good night."
There are all kinds of devices.
Some devices can measure sleep quality with great accuracy.
The three key points are:
1) How long you sleep is most important.
2) Concentrate on removing factors that degrade your sleep.
3) Consider visualization of
the quality of your sleep.
Kao nashi wants to know why people dream.
The immediate answer is "No one really knows."
Dreams you can recall vividly are dreams you dreamt during REM sleep.
Oftentimes, dreams are not pleasant, rather very stressful.
Some people say dreams help you cope with stress happening in real life.
Sort of like image training.
Some studies show that those who dream a lot are stress tolerant.
Other studies show that PTSD patients who dream often
heal quicker than those who don't.
Lots of reports like that.
So keep in mind that bad dreams aren't necessarily all that bad for you.
Onto the next question.
"Why do we forget our dreams when we wake up?"
During REM sleep, our brains try to forget unimportant information.
We're doing this all the time.
In most cases, we don't remember these brain activities.
But we are always dreaming during REM sleep.
It's just that we forget.
When we remember the brain activities we consider them as our dreams.
If we don't sleep, then we can't de-clutter our memories.
That's why sleep is important.
If you have a test coming up, you'll be able to remember things more clearly
if you sleep on it for a day.
Memories acquired in this way are known as procedural memories.
It's to retrieve information to perform learned skills like sports.
These memories get refined during your sleep.
You may have had an experience where you couldn't play a certain musical passage
but was able to play without difficulty the day after.
Quite fascinating, right?
This is how the brain gets rid of "excess" information.
The reason we forget our dreams is
because our brain tries to forget during REM sleep.
This is from Gaiken Shoyu.
"Will it be possible to record our dreams?"
You may say that it is already possible to record dreams.
Quite a few years back,
a team at Kyoto University published an innovative journal article.
You see, an MRI is capable of producing images of your brain functions.
At the very back of your brain is the visual cortex.
The Kyoto team demonstrated that dreamed objects can be predicted by
decoding functional MRI data of activities in the visual cortex.
In other words, they had someone sleep in an MRI
and guessed what he dreamt from functional MRI data of his brain.
Then verified their analysis by asking what he had dreamt.
It's quite an accomplishment.
And along this line,
we may be able to see our dreams in form of a short movie.
pp wants to know
"How long of a nap is most effective when we're feeling tired?"
I usually recommend 20 minutes.
You may wonder "Why 20 minutes?"
The first stage of sleep is known as light sleep.
Then we enter deeper sleep known as Stage 2 non-REM sleep.
Waking up after several minutes of deeper sleep is most effective.
Because after more than 20 minutes,
your sleep cycle enters Stage 3, the deepest sleep phase.
It takes time to wake up from this phase and is extremely unpleasant.
You wouldn't want to wake up.
So if you want to take a nap,
it's best to sleep for about 15 to 20 minutes.
World wants to know,
"What kind of organisms need sleep and what kind doesn't?"
Those with a nervous system need sleep.
For example, jelly fish.
Jelly fish move their tentacles sending signals through nerves.
But they don't have any brains.
And yet, jelly fish need to sleep.
Organisms without a nervous system,
such as microorganisms,
do not take any behavior that we define as sleep.
Tetrapod asks,
"Why did nature not eliminate sleeping in the course of evolution?"
Such a great question.
I want to know why too.
When we are asleep, we're not conscious, making us very vulnerable.
Yet, our instincts choose to sleep, despite all the risks.
What is it that we have to do while sleeping
even under such conditions?
The truth is, no one really knows what we have to do.
Even with all these technologies!
Puri puri asks,
"Why is there a difference in hours of sleep among organisms?"
I think it's rooted in the organism.
It's an example of what we call an evolutionary niche.
The hours of sleep an organism finds to be optimal are
the result of evolution of that particular type of species.
Large herbivores such as cows and horses
are known to sleep for only about 2 to 4 hours a day.
One reason why it's short is
because they need to eat all day long to keep them nourished with grass.
Plus, it's hard to hide their big body.
They need to keep alert to protect themselves from carnivores.
That's probably why they don't sleep much.
It's different for carnivores,
such as lions or even pet cats at a more domestic level.
These animals tend to need longer hours of sleep.
They focus on hunting while they are awake.
They eat the meat they caught and then sleep afterwards.
But they don't need to be afraid of predators.
The difference in hours of sleep
strongly depends on the evolutionary niche that the organism occupies.
Japanese get sleepy during the day.
They get sleepy during boring meetings and lectures.
You might think this is normal, but it's not in global standards.
Because if you're getting enough sleep, you don't get sleepy during the day.
If you do get sleepy, that means you're starting to lack sleep.
Make sure to allocate time for sleep,
and get a good night's rest.
Thank you everyone.