So there are probably many mechanisms, but one of the ones that is best understood is that we know that when you're sleep-deprived, or indeed when your sleep is disrupted by anything else like, for example, sleep apnea, there are changes that occur in terms of hormone levels of hormones that regulate our appetite and our satiety. And so even a single night of sleep deprivation can result in a dramatic increase in your calorie intake overnight.

おそらく多くのメカニズムがあると思われるが、最もよく理解されているのは、睡眠不足、あるいは睡眠時無呼吸症候群などで睡眠が妨げられると、食欲や満腹感を調節するホルモンレベルに変化が起こるということだ。そのため、たった一晩の睡眠不足でも、一晩で摂取カロリーが劇的に増加する可能性がある。

There have been some studies done, for example, in nurses. So there was a study done that followed up nurses for 18 years, and they looked at their weight and how much they slept on a regular basis. And what they found is that those nurses that were sleeping less than about six hours a night on a regular basis, first of all, started off at the beginning of that 18-year period at a slightly higher weight. But over the course of those 18 years, they put on much more weight than other groups. So there is a very clear correlation between sleep duration, sleep quality, and weight gain. We see that, for example, in individuals who we treat with sleep apnea. So one of the treatments for sleep apnea is a mask-like device that you wear that stops your airway from closing down at night. And for some very overweight individuals, actually, when you treat their sleep apnea, they do manage to successfully lose weight, where in the past they found it absolutely impossible to do so.

例えば、看護師を対象にした研究があります。看護師を18年間追跡調査し、体重と定期的な睡眠時間を調べた研究があります。その結果、定期的な睡眠時間が6時間未満の看護師は、まず18年間の最初の段階では体重がやや多いことがわかった。しかし、その18年間の間に、他のグループよりもはるかに体重が増加した。つまり、睡眠時間、睡眠の質、体重増加には非常に明確な相関関係があるのだ。例えば、私たちが睡眠時無呼吸症候群の治療を行っている人たちにもその傾向が見られます。睡眠時無呼吸症候群の治療法のひとつに、夜間に気道が閉じるのを

Okay, so if I'm underslept, I'm more likely to eat more calories the next day. Am I also more likely to reach for foods that are high in sugar and bad for me?

なるほど、寝不足だと翌日のカロリーが高くなりやすいのですね。また、糖分が多く体に悪い食べ物に手が伸びやすいのでしょうか？

Certainly some studies do suggest that. I think it's also important to say that sleep disruption or sleep deprivation has some fundamental effects, for example, on your glucose tolerance, so your insulin resistance, which of course is a particular issue for people with diabetes, but it affects us all. So if you're very sleep deprived, there are changes to the way that not only your appetite or what you're reaching for, but also how your body processes the breakdown of those foodstuffs.

確かに、それを示唆する研究もあります。睡眠障害や睡眠不足は、例えば耐糖能やインスリン抵抗性に根本的な影響を与えるということも重要だと思います。ですから、睡眠不足がひどいと、食欲や手を伸ばすものだけでなく、その食材の分解を体がどのように処理するかも変わってきます。

Interesting. Because anecdotally, I think I can clearly say that if I'm underslept,

興味深い。というのも、逸話的には、寝不足だとはっきりそう言えると思うんだ、

I'm much more likely to eat something that is high in sugar or is not good for me.

糖分が多かったり、体に良くないものを食べることの方がずっと多い。

We can all testify to that, can't we? I think everybody has known that situation where they're very sleep deprived and they think, oh, well, I just need a bit of chocolate.

それは誰もが経験することだろう。寝不足で、ああ、チョコレートをちょっとだけ食べたい。

What's going on in the brain, though? Is it something to do with the amygdala and the prefrontal cortex, the emotional centre of our brain?

脳の中で何が起こっているのだろう？脳の感情中枢である扁桃体や前頭前皮質と関係があるのだろうか？

Yeah, I don't think we know. I think it's probably to do with the reward mechanisms that underlie our behaviours, that there is something about sleep deprivation that alters the rewards that we're seeking. But I don't think I can give you a clear answer on that.

そうだね。おそらく私たちの行動の根底にある報酬のメカニズムに関係しているのだと思う。睡眠不足には、私たちが求める報酬を変化させる何かがあるのだろう。でも、それについて明確な答えを出せるとは思わない。

You also talked about circadian rhythms. If I was a 10-year-old, what do I need to understand about the circadian rhythm? What it is, what it does, and why it's important?

サーカディアンリズムについても話してくれましたね。もし私が10歳だったら、概日リズムについて何を理解する必要がありますか？サーカディアンリズムとは何なのか、サーカディアンリズムが何をするのか、そしてなぜサーカディアンリズムが重要なのか。

Within pretty much every cell of our bodies, there is this 24-hour clock. In fact, if you take a single cell and stick it in a Petri dish, about 40% of the genes within that cell will exhibit this 24-hour cycle. That 24-hour cycle really controls pretty much every biological system within our bodies, be it how our liver works, how our heart works, how our lungs work.

私たちの体のほとんどすべての細胞の中に、この24時間時計がある。実際、一つの細胞をペトリ皿に入れると、その細胞内の遺伝子の約40％がこの24時間周期を示す。この24時間サイクルは、肝臓の働き、心臓の働き、肺の働きなど、私たちの体内のほとんどすべての生体システムをコントロールしているのだ。

There is one particular area of the brain called the suprachiasmatic nucleus that is viewed as the master clock. It's the clock that coordinates all the other clocks within our bodies. That influences not only all of these other clocks that are occurring within the cells throughout our bodies, but influences our behaviour as well. It influences, generally speaking, when we feel tired, when we want to go to bed, and when we wake up. It also influences things like when we feel most mentally alert, when we want to eat, when we want to drink, when we feel most able to cope with work, for example. Now, that circadian rhythm, that circadian clock, for most people, confers the sleep onset of somewhere between 10pm and midnight, if you're an adult, and waking up somewhere between 6am and 8am. Now, the timing of that body clock is governed by two things. It's governed by our genetics, so whether or not we are genetically predetermined to be slightly later in terms of our body clock or slightly earlier.

視交叉上核と呼ばれる脳のある部位は、マスタークロックとみなされている。私たちの体内の他のすべての時計を調整する時計だ。それは、私たちの体中の細胞内で起こっている他の時計すべてに影響を与えるだけでなく、私たちの行動にも影響を与える。一般的に言えば、疲れを感じる時間、寝たくなる時間、目覚める時間に影響を与える。また、精神的に最も冴えていると感じる時、食べたくなる時、飲みたくなる時、仕事に最も対処できると感じる時などにも影響を与える。さて、この概日リズム、概日時計は、ほとんどの人にとって、成人であれば午後10時

We see that in families where lots of people, for example, will say, you know, I've always gone to bed late and woken up late, but so has my father, so has my grandfather, etc, etc. But it's also influenced by what's happening in our environment.

例えば、私はいつも寝るのが遅く、起きるのも遅いが、父もそうだったし、祖父もそうだった。でも、環境にも影響されるんだ。

About 50% of the definers of our circadian clock are governed by what's going on around us, be that in terms of when we're exposed to light, so we know that light is a very important driver of our circadian rhythm, when we're eating, when we're exercising, when we're doing a whole range of other activities. And also, one of the markers of our circadian rhythm is the secretion of melatonin. So, there's a very small gland in the centre of our brains called the pineal gland, which secretes a hormone called melatonin. That hormone tends to start being secreted in most people at around 6 o'clock in the evening. It peaks at the time that we want to go to sleep, and then it starts dropping down a few hours before we wake up. It's almost a chemical marker of our circadian rhythm. But we also know that giving people melatonin in tablet form, for example, can influence our circadian rhythm. So, there's this sort of feedback loop between our own body's secretion of melatonin and what our suprachiasmatic nucleus, our master clock, is doing. So, by giving people melatonin at particular times of the day, we can shift your circadian rhythm forward or back. So, that master clock in the brain, where is it positioned?

つまり、光は概日リズムの非常に重要な原動力であり、食事をしている時、運動をしている時、その他さまざまな活動をしている時などである。また、概日リズムの指標のひとつにメラトニンの分泌がある。私たちの脳の中心には松果体というとても小さな腺があり、メラトニンというホルモンを分泌している。このホルモンは、ほとんどの人が夕方6時ごろに分泌され始める傾向がある。私たちが眠たくなる時間にピークを迎え、それから目覚める数時間前に下がり始める。これは、私たちの概日リズムの化学的な目印のようなものです。しかし、例えば錠剤のメラ

The suprachiasmatic nucleus is in a small area of the brain called the hypothalamus.

視交叉上核は視床下部と呼ばれる脳の小さな領域にある。

And is that linked to the eye? There are links from the back of the eye to the hypothalamus. So, there are some cells in the back of the eye, in the retina, that are not involved in vision, not involved in conscious vision. But what they are involved with is detecting blue light in particular, which is the part of the spectrum of light that is most important in terms of regulating our circadian clock. And there are direct links between these cells that are called retinal ganglion cells and the suprachiasmatic nucleus.

それは眼球とつながっているのですか？目の奥から視床下部までつながっている。つまり、目の奥の網膜には、視覚や意識的な視覚には関与しない細胞がある。しかし、これらの細胞が関わっているのは、特に青色光を感知することである。青色光は光のスペクトルの中で、概日時計を調節する上で最も重要な部分である。そして、網膜神経節細胞と呼ばれるこれらの細胞と視交叉上核との間には直接的なつながりがある。

So, exposure to light, to blue light in particular, is really very important in reinforcing or adjusting our circadian rhythm. Now, of course, we live in a world whereby the seasons change, and the amount of light that we're exposed to changes. So, if we were on a set rhythm all the time that was immovable and unadjustable, then there would be times where our circadian rhythm might be at odds with our environment. So, there does need to be some slight adjustment of that circadian rhythm, and light is probably the most important adjuster.

つまり、光、特に青い光を浴びることは、概日リズムを強化したり調整したりする上で非常に重要なのだ。もちろん、私たちは季節が変わり、浴びる光の量も変わる世界に生きている。そのため、もし私たちが常に決まったリズムを刻んでいて、それが不変で調整不可能だとしたら、私たちの概日リズムが環境と相容れないことがあるかもしれない。そのため、概日リズムをわずかに調整する必要がある。

Blue light, is that the light that comes from my smartphone?

ブルーライト、それはスマートフォンから出る光ですか？

So, blue light, obviously, the strongest source of blue light is sun. But yes, these kinds of devices, your smartphone, your iPad in front of you, a range of electronic devices also have blue light within them. So, that's why if I'm up on my phone until 1am in the morning, staring into the screen, I'm kind of tricking that sort of optic nerve, which is then impacting my master clock, and I'm telling it that it's a different time.

ブルーライトの最も強い発生源は太陽です。しかし、スマートフォンやiPadなど、さまざまな電子機器にもブルーライトは含まれています。だから、夜中の1時までスマホをいじり、画面を見つめていると、視神経がだまされ、マスタークロックに影響を与え、違う時間になったと錯覚してしまうのだ。

Yeah, so the thinking on that has changed a little bit over the last few years. So, you know, it was said that using these devices will trigger insomnia as a result of blue light.

ここ数年で考え方が少し変わってきているんだ。このような機器を使うと、ブルーライトの影響で不眠症になると言われていました。

Actually, it's likely that the amount of blue light that these devices put out is probably insufficient to do that directly. But there are two effects of using your gadget until 1am. The first is on a long-term basis, if you're doing that regularly, it will result in an adjustment of your circadian clock and push it back. So, you will want to go to bed a little bit later and wake up a little bit later, which is fine if you're self-employed or you don't have any restrictions on your time. But most of us need to be up at a certain time in the morning. And if your circadian rhythm is delayed significantly, the net effect of that is that you're going to end up sleep deprived. I mean, there's also the issue of being, you know, on Twitter or being engrossed in a movie on Netflix at 1am that is going to make you delay sleep anyway. So, there are those two effects. It's arousing and it grips your attention.

実際、これらの機器が発するブルーライトの量は、直接的にそれを行うには不十分だろう。しかし、午前1時までガジェットを使用することには2つの影響がある。1つ目は、長期的に見た場合、定期的に使用していると、概日時計が調整され、遅らせることになる。つまり、寝る時間を少し遅くし、起きる時間を少し遅くしたくなるのだ。自営業や時間に制約がない場合は問題ない。しかし、ほとんどの人は朝決まった時間に起きる必要がある。概日リズムが大幅に遅れると、睡眠不足に陥ってしまう。また、夜中の1時にツイッターを見たり、ネットフリックスで

Well, what do you make of these people, me being one of them, that watch, you know, serial killer movies when we fall asleep?

私もその一人なんだけど、眠りにつくときに連続殺人犯の映画を見る人たちをどう思う？

Well, I think that that's only an issue if it's stopping you from falling asleep.

まあ、それが問題になるのは、入眠を妨げる場合だけだと思う。

Because I have this argument a lot with my partner. She can't understand why I need to watch this, like, really stimulating stuff when I fall asleep. She likes quiet and I need to,

というのも、私はパートナーとよく口論になるんだ。彼女は、なぜ私が眠りにつくときに、このような、本当に刺激的なものを見る必要があるのか理解できないんだ。彼女は静かなのが好きなのに、僕は必要なんだ、

I tell myself I need to, like, listen to something. Do you see, like, variance in this kind of thing? And is there a better approach?

自分に言い聞かせるんだ。このようなことにばらつきはありますか？また、もっと良いアプローチはありますか？

This comes down to an individualised approach to sleep. And that's why I'm always very reluctant to say this is the perfect night's sleep. These are the rules for sleep. You know, for example, there are some people who, for whom caffeine doesn't really influence their sleep and can have a double espresso an hour before bed and still have no problems getting off to sleep. For most of us, that's not the case. If you are somebody who can watch something very stimulating, very scary, and then switch it off and roll over and go off to sleep, then I guess that's not a problem for you. For most people, that's probably not the best thing to be doing at night. I think that long term, one of the issues is with all of these kinds of activities in bed at night before you go off to sleep, is that they weaken the psychological associations between bed and sleep. And so if you start associating bed being a place where you're mentally active, where you're engaged, then if you have an underlying predisposition to insomnia, for example, then that can sometimes set the stage for developing insomnia later on. The average person that you've treated, worked with in your clinical practice that's struggling with sleep, is at the heart of the issue just poor sleep hygiene, like you've said there. Because I've got so many friends that say to me that they struggle with their sleep. Many of them have struggled with it for years. And I doubt that there's some sort of genetic reason why this many people are struggling with sleep. So I imagine it's just some kind of behavioural reason. So I think that the genes that predispose to insomnia are pretty widespread, but obviously, you know, in pretty much all areas of medicine, there is an interaction between genetics and environment. And certainly poor sleep hygiene, and that's a horrible term,

これは睡眠に対する個々のアプローチに起因する。だからこそ、私はいつもこれが完璧な睡眠だと言うことに抵抗がある。これが睡眠のルールです。例えば、カフェインが睡眠にあまり影響を与えないという人もいるし、寝る1時間前にダブルのエスプレッソを飲んでも問題なく眠れるという人もいる。ほとんどの人はそうではない。とても刺激的で、とても怖いものを見ても、スイッチを切って寝返りを打ち、眠りにつくことができる人なら、それは問題ないだろう。ほとんどの人にとって、夜中にすることはベストではないだろう。長期的な問題として、夜寝る前

I hate that term, but it's the term that is most widely used and understood, can certainly put in place certain aspects of behaviour that then can give rise to chronic insomnia in the long term.

私はこの言葉が嫌いだが、最も広く使われ、理解されている言葉であり、長期的に慢性不眠症の原因となるある種の行動を引き起こす可能性がある。

So if you've got very bad chronic insomnia, then suddenly, putting good sleep hygiene in place is unlikely to fix it. But it may be that that poor sleep hygiene in the first instance gave rise or at least predisposed you to developing insomnia.

ですから、慢性的な不眠症がとてもひどい場合、いきなり良い睡眠衛生を整えても直る可能性は低いのです。しかし、最初の段階で睡眠衛生状態が悪かったために、不眠症になったか、少なくとも不眠症になる素因があったのかもしれません。

And what is poor sleep hygiene? If I wanted to be the worst possible sleeper in the world, what would I have to do?

また、睡眠衛生の悪さとは何だろう？もし私が世界一寝つきの悪い人間になりたかったら、どうすればいいのだろう？

So I think you would probably have to set up your home office in your bedroom.

だから、おそらく寝室にホームオフィスを構えることになると思う。

Okay.

オーケー。

You'd have to have, you know, your TV on in your bedroom all the time.

寝室で常にテレビをつけていなければならない。

Okay.

オーケー。

And be surrounded by electronic devices. Drink a lot of coffee late in the evening.

そして電子機器に囲まれる。夜遅くにコーヒーをたくさん飲む。

Alcohol.

アルコールだ。

Drink a little bit of alcohol. So alcohol in the short term, of course, is quite sedating.

アルコールを少し飲む。だから、短期的なアルコールは、もちろん、かなり鎮静作用がある。

It's a central nervous system depressant. But it does dramatically worsen the quality of your sleep and for various reasons, the direct chemical effect, the fact that you've got a full bladder, and the fact that you're probably snoring a little bit more. So alcohol is not a good thing.

中枢神経抑制剤だ。しかし、睡眠の質を劇的に悪化させます。直接的な化学的影響、膀胱がいっぱいになっていること、いびきが少し多くなっていることなど、さまざまな理由があります。ですから、アルコールは良いものではありません。

You know, not having a wind down period. So, you know, gambling on the stock market until 1am, switching your laptop and then trying to go to bed.

つまり、ダウンタイムがないんだ。夜中の1時まで株式市場でギャンブルをして、ノートパソコンを切り替えて、それから寝ようとする。

Those kinds of things. So that's, you know, the quintessential, very, very bad sleep hygiene.

そういうことだ。つまり、これは典型的な、とてもとても悪い睡眠衛生なんだ。

What about when I eat?

食事の時はどうだろう？

So, you know, eating is perhaps less important, but avoiding a very large carbohydrate meal, carbohydrate rich meal before you go to bed for two reasons. One is that we know that it can cause some fluctuations in terms of your blood sugar. And also, if you've got a bit of reflux, it can make that much worse.

だから、食事はそれほど重要ではないかもしれないが、寝る前に炭水化物を多く含む食事は避けることだ。ひとつは、血糖値の変動を引き起こす可能性があるということ。また、逆流しやすい人は、逆流がひどくなる可能性があります。

Okay. What about sleeping in bed with somebody else?

そうですか。誰かと一緒にベッドで寝るのはどう？

Well, I think that for some people they find, again, this goes back to no one rule for everybody.

まあ、人によっては、誰にでも当てはまるルールはないということに気づく人もいると思う。

You know, if you've got a sleep trait termed sleep reactivity, which is where your sleep is very liable to your environment, then obviously sleeping next to somebody who's snoring loudly, or who gets up in the middle of the night two or three times to urinate can be very disruptive to your sleep. If you've got very little sleep reactivity, you may actually find it comfortable, more comfortable to sleep with somebody in the same bed as you.

睡眠反応性と呼ばれる睡眠特性があり、睡眠が環境に大きく左右される場合、大きないびきをかいている人の隣で寝たり、夜中に2、3回排尿のために起きたりすると、明らかに睡眠が妨げられる。睡眠反応性がほとんどない人は、同じベッドで誰かと一緒に寝る方が快適で、より快適に感じるかもしれない。

I was thinking the other day, because where I've currently moved into, there's no blinds or curtains in my bedroom. And I was wondering if that might be a good thing.

先日考えたんだけど、今引っ越してきた場所には寝室にブラインドもカーテンもないんだ。それはいいことなのかなと思ったんだ。

Because it at least means that in terms of my circadian rhythm,

少なくとも私の概日リズムという意味ではそうだからだ、

I'm waking up at the same time every day. Because I'm waking up when the sun comes up.

私は毎日同じ時間に起きている。太陽が昇ると目が覚めるから。

Yeah, but the sun comes up at different times on different days, firstly. So if you were doing that routinely, you might find yourself really rather sleep deprived in the summer months. And also, there is some emerging evidence that exposure to light at night in your sleep is not very good for you. So there was a very recent study that implied that light exposure at night increases your risk of diabetes. So it certainly is not good for the quality of your sleep. And the likelihood is that you won't wake up as soon as it's light, you'll wake up at an hour or so after it's got light, but during that hour or so, it may have had a negative impact on the quality of your sleep.

ああ、でも、まず日の出の時間が日によって違う。だから、それを日常的にやっていたら、夏の間は本当に睡眠不足になるかもしれない。また、夜寝ている間に光を浴びるのはあまり良くないという証拠も出てきている。ごく最近の研究で、夜間に光を浴びると糖尿病のリスクが高まることが示唆されました。つまり、睡眠の質には良くないということです。明るくなってすぐに目が覚めるわけではなく、明るくなってから1時間かそこらで目が覚めますが、その1時間かそこらの間に、睡眠の質に悪影響を及ぼしている可能性があります。

So having a dark bedroom is really part of good sleep hygiene, as it's having a quiet bedroom that is not too hot or too cold. What if you wear a sleep mask? Does that solve it? Yes, it does. I mean, I wear a sleep mask. I think it's, you know, particularly if you don't have good blackout curtains or blinds in your bedroom, using a sleep mask, particularly in the summer months, is probably very helpful indeed. Does that mean that the only light receptors we have are behind our eyes? Well, I think that there was a, there were some rumours on the internet that there were light receptors elsewhere, but certainly the only ones that we know to be of significance in terms of defining our circadian rhythm are the ones in our retinas. If you love the DRIVERS CEO brand and you watch this channel, please do me a huge favour, become part of the 15% of the viewers on this channel that have hit the subscribe button. It helps us tremendously, and the bigger the channel gets, the bigger the guests.

ですから、寝室を暗くすることは、暑すぎず寒すぎない静かな寝室を確保することと同じように、良い睡眠衛生の一部なのです。スリープマスクをしたらどうですか？それで解決しますか？はい、解決します。私はスリープマスクをしています。特に寝室に遮光カーテンやブラインドがない場合は、特に夏場はスリープマスクを使うのが効果的だと思います。ということは、光の受容体は目の奥にしかないということですか？インターネット上では、他の場所にも光受容体があるという噂もあったようですが、私たちの概日リズムを決定する上で重要であることがわか