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  • Thank you very much.

    翻訳: Moe Shoji 校正: Midori T

  • Well, I would like to start with testicles.


  • (Laughter)


  • Men who sleep five hours a night


  • have significantly smaller testicles than those who sleep seven hours or more.

    夜に5時間しか 眠らない男性の睾丸は

  • (Laughter)

    7時間以上眠る男性に比べると かなり小さいのです

  • In addition, men who routinely sleep just four to five hours a night


  • will have a level of testosterone

    さらに 日常的に夜に 4~5時間しか寝ない男性の

  • which is that of someone 10 years their senior.


  • So a lack of sleep will age a man by a decade


  • in terms of that critical aspect of wellness.

    睡眠不足が続くと この健康上重要な点から見て

  • And we see equivalent impairments in female reproductive health


  • caused by a lack of sleep.

    女性の生殖機能に関する健康も 睡眠不足によって

  • This is the best news that I have for you today.


  • (Laughter)


  • From this point, it may only get worse.


  • Not only will I tell you about the wonderfully good things

    ここからは悪くなる一方 かもしれません

  • that happen when you get sleep,

    十分な睡眠がもたらす 素晴らしく良いことを

  • but the alarmingly bad things that happen when you don't get enough,


  • both for your brain and for your body.

    睡眠不足によって 脳と身体の両方に起こる―

  • Let me start with the brain

    驚くほど悪いことについても お話しするからです

  • and the functions of learning and memory,

    まずは 脳と

  • because what we've discovered over the past 10 or so years

    学習や記憶の機能について お話ししましょう

  • is that you need sleep after learning

    過去10年ほどの研究によって 明らかになったのは

  • to essentially hit the save button on those new memories

    学習後に睡眠が 必要だということでした

  • so that you don't forget.

    いわば「保存」ボタンを押して 新しく学習した内容を

  • But recently, we discovered that you also need sleep before learning


  • to actually prepare your brain,

    最近分かったのは 学習前にも 睡眠が必要だということです

  • almost like a dry sponge


  • ready to initially soak up new information.


  • And without sleep, the memory circuits of the brain

    新しい情報を吸収する準備を 整えるのです

  • essentially become waterlogged, as it were,

    睡眠不足だと 脳の記憶回路は

  • and you can't absorb new memories.


  • So let me show you the data.


  • Here in this study, we decided to test the hypothesis


  • that pulling the all-nighter was a good idea.


  • So we took a group of individuals

    「徹夜には利点がある」 という仮説です

  • and we assigned them to one of two experimental groups:


  • a sleep group and a sleep deprivation group.

    2つの実験グループに 振り分けました

  • Now the sleep group, they're going to get a full eight hours of slumber,

    睡眠グループと 睡眠不足グループです

  • but the deprivation group, we're going to keep them awake

    睡眠グループは たっぷり8時間の睡眠をとります

  • in the laboratory, under full supervision.

    睡眠不足グループは 実験室で監視下に置き

  • There's no naps or caffeine, by the way, so it's miserable for everyone involved.


  • And then the next day,

    昼寝もカフェインも禁止なので 被験者には辛い状況です

  • we're going to place those participants inside an MRI scanner


  • and we're going to have them try and learn a whole list of new facts


  • as we're taking snapshots of brain activity.

    彼らに新しい事柄を 学習させている間に

  • And then we're going to test them

    脳の活動の様子を 画像に収めるんです

  • to see how effective that learning has been.


  • And that's what you're looking at here on the vertical axis.


  • And when you put those two groups head to head,

    このグラフの縦軸は 学習効果です

  • what you find is a quite significant, 40-percent deficit

    2つのグループの結果を 並べてみると

  • in the ability of the brain to make new memories without sleep.

    睡眠をとらなかったグループは 脳に新しい記憶を定着させる能力が

  • I think this should be concerning,

    実に 40%も下回っています

  • considering what we know is happening to sleep


  • in our education populations right now.


  • In fact, to put that in context,

    睡眠の取り方を 考えてみてください

  • it would be the difference in a child acing an exam


  • versus failing it miserably -- 40 percent.

    40%もの差があれば テストで好成績を収めるのと

  • And we've gone on to discover what goes wrong within your brain


  • to produce these types of learning disabilities.

    それから 脳で何が 起きているせいで

  • And there's a structure that sits

    こうした学習障害が 起きるのかを探りました

  • 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

    いわば 脳における 情報の受信箱です

  • and then holding on to them.

    新しい記憶ファイルを受け取り 貯蔵するのに

  • And when you look at this structure


  • in those people who'd had a full night of sleep,

    たっぷり睡眠をとった人々の 脳の海馬では

  • we saw lots of healthy learning-related activity.

    学習に関連した健康な活動が 多く見られました

  • Yet in those people who were sleep-deprived,

    しかし 睡眠不足の人々では

  • we actually couldn't find any significant signal whatsoever.

    有意な信号が まったく見られなかったのです

  • So it's almost as though sleep deprivation had shut down your memory inbox,

    睡眠不足によって 記憶の受信箱が閉鎖されてしまい

  • and any new incoming files -- they were just being bounced.

    新しいファイルを 受け付けなかったようなものです

  • You couldn't effectively commit new experiences to memory.

    新たな経験を効果的に 記憶することができないのです

  • So that's the bad that can happen if I were to take sleep away from you,

    睡眠不足だと このような悪いことが起きるのですが

  • but let me just come back to that control group for a second.

    対照実験グループに いったん話を戻しましょう

  • Do you remember those folks that got a full eight hours of sleep?

    たっぷり8時間の睡眠をとった グループがいましたよね?

  • Well, we can ask a very different question:

    今度は別の問いを 立ててみましょう

  • What is it about the physiological quality of your sleep

    睡眠をとった場合に 睡眠のどんな生理学的性質によって

  • when you do get it

    記憶や学習能力が 日々 回復し 改善されるのでしょう?

  • that restores and enhances your memory and learning ability

    頭部に電極を たくさんつけてみると

  • each and every day?


  • And by placing electrodes all over the head,

    大きく力強い脳波が 観察されました

  • what we've discovered is that there are big, powerful brainwaves


  • that happen during the very deepest stages of sleep


  • that have riding on top of them


  • these spectacular bursts of electrical activity

    この深い眠りでの脳波の 組み合わせこそが

  • that we call sleep spindles.

    夜間にファイル転送システム のように機能して

  • And it's the combined quality of these deep-sleep brainwaves

    記憶を短期記憶という やや頼りない貯水池から

  • that acts like a file-transfer mechanism at night,

    脳の長期記憶という より永続的な貯蔵庫へと移動させて

  • shifting memories from a short-term vulnerable reservoir

    記憶を守り 保護するのです

  • to a more permanent long-term storage site within the brain,

    睡眠中に 一体何が

  • and therefore protecting them, making them safe.

    こうして記憶を処理するのかを 理解することは重要です

  • And it is important that we understand

    なぜなら 医療的・社会的に 大きな意味があるからです

  • what during sleep actually transacts these memory benefits,

    この調査結果を 臨床的に応用した―

  • because there are real medical and societal implications.

    ある領域について お話しさせてください

  • And let me just tell you about one area


  • that we've moved this work out into, clinically,

    老化とともに 学習能力や記憶力が

  • which is the context of aging and dementia.

    低下し衰えるのは 誰もが知っています

  • Because it's of course no secret that, as we get older,

    しかし 老化による―

  • our learning and memory abilities begin to fade and decline.

    生理学的特徴として 睡眠の質が 低下することが分かりました

  • But what we've also discovered

    特に 先程 お話ししたような 深い眠りは得にくくなります

  • is that a physiological signature of aging is that your sleep gets worse,

    昨年になって ようやく

  • especially that deep quality of sleep that I was just discussing.

    これら2つの現象が 同時に起こるだけでなく

  • And only last year, we finally published evidence

    大いに相関があるという根拠を 発表しました

  • that these two things, they're not simply co-occurring,

    これによって分かったのは 深い眠りが妨げられることは

  • they are significantly interrelated.


  • And it suggests that the disruption of deep sleep

    記憶力の衰えが起こる 要因のひとつだということです

  • is an underappreciated factor

    そして より最近になって 分かったのですが

  • that is contributing to cognitive decline or memory decline

    アルツハイマー病にも 関係しています

  • in aging, and most recently we've discovered,

    これは非常に気分が 暗くなるようなニュースです

  • in Alzheimer's disease as well.


  • Now, I know this is remarkably depressing news.

    でも 希望の光が あるかもしれません

  • It's in the mail. It's coming at you.

    老化に関連しているとされる 他の要因とは異なるからです

  • But there's a potential silver lining here.

    例えば 物理的に構造が 変化してしまった脳は

  • Unlike many of the other factors that we know are associated with aging,

    治療することが ひどく難しいのですが

  • for example changes in the physical structure of the brain,

    老化やアルツハイマー病に 説明をつけるための手がかりが

  • that's fiendishly difficult to treat.

    睡眠であるなら 素晴らしいことです

  • But that sleep is a missing piece in the explanatory puzzle

    何か行動することが できるのですから

  • of aging and Alzheimer's is exciting

    うちの睡眠研究所には 睡眠導入剤を用いずに

  • because we may be able to do something about it.


  • And one way that we are approaching this at my sleep center

    残念ながら 睡眠導入剤は 自然な睡眠をもたらさないのです

  • is not by using sleeping pills, by the way.

    そうではなく 私たちが 発展させつつある手法では

  • Unfortunately, they are blunt instruments that do not produce naturalistic sleep.


  • Instead, we're actually developing a method based on this.


  • It's called direct current brain stimulation.

    非常に微量なので 何も感じませんが

  • You insert a small amount of voltage into the brain,


  • so small you typically don't feel it,

    若く健康な成人の睡眠中に この刺激を与えて

  • but it has a measurable impact.

    深い睡眠中の脳波の出現と 同時に刺激すると

  • Now if you apply this stimulation during sleep in young, healthy adults,

    深い眠りでの脳波の大きさを さらに増幅できるだけでなく

  • as if you're sort of singing in time with those deep-sleep brainwaves,

    睡眠から得られる記憶への効用を ほぼ2倍にすることができます

  • not only can you amplify the size of those deep-sleep brainwaves,


  • but in doing so, we can almost double the amount of memory benefit

    この安価で持ち運びが 可能になりうる技術を

  • that you get from sleep.

    老齢の人々や認知症患者に 応用できるかということです

  • The question now is whether we can translate

    深い眠りの持つ 健康な質を取り戻し

  • this same affordable, potentially portable piece of technology

    それによって 学習能力や記憶機能を 守ることができるのでしょうか?

  • into older adults and those with dementia.


  • Can we restore back some healthy quality of deep sleep,


  • and in doing so, can we salvage aspects of their learning

    以上が 脳にとっての 睡眠の役割の一例ですが

  • and memory function?

    睡眠は身体にとっても 同様に不可欠なものです

  • That is my real hope now.

    睡眠不足と生殖機能の関係については もうお話ししましたね

  • That's one of our moon-shot goals, as it were.

    睡眠不足と心臓血管系の機能の 関係についても お話ししましょう

  • So that's an example of sleep for your brain,


  • but sleep is just as essential for your body.

    年に2回 70もの国々の 16億人を巻き込んで

  • We've already spoken about sleep loss and your reproductive system.

    地球規模で行われている実験が ありますよね ―

  • Or I could tell you about sleep loss and your cardiovascular system,

    そう サマータイムです

  • and that all it takes is one hour.

    春に1時間 睡眠が短くなると

  • Because there is a global experiment performed on 1.6 billion people

    翌日に心臓発作の件数が 24%も増加します

  • across 70 countries twice a year,

    秋に1時間 睡眠が長くなると

  • and it's called daylight saving time.

    心臓発作の件数が 21%減少します

  • Now, in the spring, when we lose one hour of sleep,


  • we see a subsequent 24-percent increase in heart attacks that following day.

    全く同じパターンの変化が 自動車の衝突事故や交通事故

  • In the autumn, when we gain an hour of sleep,


  • we see a 21-percent reduction in heart attacks.

    しかし もう一歩踏み込んで 考えてほしいのは

  • Isn't that incredible?


  • And you see exactly the same profile for car crashes, road traffic accidents,

    画像に写った きれいな青いものを ご紹介しましょう

  • even suicide rates.

    ナチュラルキラー細胞と 呼ばれるものです

  • But as a deeper dive, I want to focus on this:

    ナチュラルキラー細胞は いわば免疫系統における

  • sleep loss and your immune system.


  • And here, I'll introduce these delightful blue elements in the image.

    この細胞は危険で不要なものを 見つけ出して排除するのに

  • They are called natural killer cells,


  • and you can think of natural killer cells almost like the secret service agents

    この画像は がん腫瘍を 破壊しているところです

  • of your immune system.

    力強い免疫系統の暗殺者たちに 常に目を光らせていてほしいと

  • They are very good at identifying dangerous, unwanted elements


  • and eliminating them.

    残念ながら 睡眠不足だと それは無理な相談なのです

  • In fact, what they're doing here is destroying a cancerous tumor mass.

    さて この実験では

  • So what you wish for is a virile set of these immune assassins

    一晩中 徹夜するのではなく

  • at all times,

    たったひと晩 睡眠時間を 4時間に減らして

  • and tragically, that's what you don't have if you're not sleeping enough.

    免疫細胞の活動に どのような減少が見られるかを

  • So here in this experiment,


  • you're not going to have your sleep deprived for an entire night,

    差は些細なものではなく 10%とか

  • you're simply going to have your sleep restricted to four hours


  • for one single night,

    ナチュラルキラー細胞の活動が 70%も減少していたのです

  • and then we're going to look to see what's the percent reduction


  • in immune cell activity that you suffer.


  • And it's not small -- it's not 10 percent,

    睡眠不足と様々な種類の がんの発症リスクは

  • it's not 20 percent.

    大いに関連していると 判明しつつあるのです

  • There was a 70-percent drop in natural killer cell activity.

    現在 関連が分かっているものには 大腸がんや

  • That's a concerning state of immune deficiency,


  • and you can perhaps understand why we're now finding

    実は 睡眠不足とがんの関連性が 非常に高いために

  • significant links between short sleep duration


  • and your risk for the development of numerous forms of cancer.

    夜間勤務を伴う あらゆる仕事を

  • Currently, that list includes cancer of the bowel,

    発がん性があると 分類しています

  • cancer of the prostate and cancer of the breast.


  • In fact, the link between a lack of sleep and cancer is now so strong

    例の古い格言を 聞いたことがあるかもしれません

  • that the World Health Organization


  • has classified any form of nighttime shift work


  • as a probable carcinogen,

    これは致命的に あさはかな助言です

  • because of a disruption of your sleep-wake rhythms.

    何百万人もを対象にした 疫学的研究から明らかです

  • So you may have heard of that old maxim


  • that you can sleep when you're dead.

    睡眠時間が短ければ短いほど 寿命も短くなるのです

  • Well, I'm being quite serious now --

    短時間睡眠には 様々な死亡リスクがあります

  • it is mortally unwise advice.

    がんやアルツハイマー病を 発症するリスクが

  • We know this from epidemiological studies across millions of individuals.


  • There's a simple truth:

    それでもまだ不安を かきたてられないなら

  • the shorter your sleep, the shorter your life.


  • Short sleep predicts all-cause mortality.

    睡眠不足によって蝕まれるのは 生命の構造そのものです

  • And if increasing your risk for the development of cancer


  • or even Alzheimer's disease

    また ある研究では 健康な成人を集め

  • were not sufficiently disquieting,


  • we have since discovered that a lack of sleep will even erode


  • the very fabric of biological life itself,

    それから遺伝子活動に見られた 変化を測定して

  • your DNA genetic code.

    同じ被験者が たっぷり8時間

  • So here in this study, they took a group of healthy adults

    睡眠をとった時と 比較したのです

  • and they limited them to six hours of sleep a night

    重要な発見が 2つありました

  • for one week,

    1つめに 711個もの遺伝子の活動が

  • and then they measured the change in their gene activity profile


  • relative to when those same individuals


  • were getting a full eight hours of sleep a night.

    2つめに その遺伝子の 半数ほどの活動が

  • And there were two critical findings.


  • First, a sizable and significant 711 genes

    もう半分は活動が 減少していました

  • were distorted in their activity,

    睡眠不足によって 活動が減った遺伝子は

  • caused by a lack of sleep.

    免疫機能と関わりのある 遺伝子でした

  • The second result was that about half of those genes

    ここでも 免疫不全が 起こっていることが分かります

  • were actually increased in their activity.

    対照的に 睡眠不足によって

  • The other half were decreased.

    亢進が見られ 活動が活発になった遺伝子は

  • Now those genes that were switched off by a lack of sleep


  • were genes associated with your immune system,

    体内の慢性的炎症に 関する遺伝子や

  • so once again, you can see that immune deficiency.


  • In contrast, those genes that were actually upregulated

    その結果 心血管疾患を 誘発するようなものです

  • or increased by way of a lack of sleep,

    端的に言って 睡眠不足である場合に

  • were genes associated with the promotion of tumors,

    それを免れて悪影響を受けずに 健康でいることは

  • genes associated with long-term chronic inflammation within the body,


  • and genes associated with stress,

    家の壊れた 水道管のようなものです

  • and, as a consequence, cardiovascular disease.

    睡眠不足は 生理機能の隅々の

  • There is simply no aspect of your wellness


  • that can retreat at the sign of sleep deprivation

    日々の健康を形作っている DNAの核酸の配列さえ

  • and get away unscathed.


  • It's rather like a broken water pipe in your home.

    ここまで聞いて こう思うかもしれません

  • Sleep loss will leak down into every nook and cranny

    「なんてことだ 睡眠の質をどう上げたらいい?

  • of your physiology,


  • even tampering with the very DNA nucleic alphabet

    有害で悪影響をもたらす アルコールやカフェインを

  • that spells out your daily health narrative.


  • And at this point, you may be thinking,

    夜 なかなか寝られないのなら