Why a 爆破 of morning light is the 重要な to better sleep: Professor Russell Foster, one of Britain's 主要な 専門家s, 明らかにする／漏らすs how resetting your 団体／死体 clock can revolutionise your slumber ― and it's easier than you think...

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When people find out that my work 伴う／関わるs sleep, often the first thing they want to know is: What is the secret to getting enough of it?

The answer can be 複雑にするd, but one of the most important factors, counterintuitive though it might sound, is getting the 権利 量 of light at different times of the day.

But that is 存在 土台を崩すd by modern life. Most of us assume that we humans are above the 生物学の 支配するs that dictate the activities of the 残り／休憩（する） of life on Earth ― and that we can do what we want, at どれでも time we choose.

This 仮定／引き受けること underpins our 24/7 society, and an economy that’s 扶養家族 upon people working at night to 在庫／株 our supermarkets, clean our offices, run our 全世界の 財政上の services, 修理 our rail and road 組織／基盤／下部構造, 持続する the 法律 and, of course, care for the sick and 負傷させるd.

The answer to getting enough sleep can be 複雑にするd as we try to squeeze in leisure activities after working hours (在庫／株 image)

Although working at night is the most obvious disruptor of sleep, many of us are also sleeping いっそう少なく as we try to squeeze more and more work and leisure activities into daily schedules already bursting at the seams. So we 押し進める these activities into the night.

Our 十分な-規模 占領／職業 of the night has been possible as a result of the 普及した commercialisation of electric light since the Fifties. This 驚くべき／特命の／臨時の and wonderful 資源 has 許すd us to 宣言する war upon the night ― and, without really 高く評価する／（相場などが）上がるing what we have done, our sleep has been the luckless 犠牲者.

Yet, as I explained in Saturday’s Daily Mail, sleep disruption can lead to serious health problems.

We are not, of course, able to do what we want at whatever time we want. Like almost all life on this 惑星, we are slaves to the rhythm 始める，決める by the Earth’s 24-hour rotation upon its axis.

All of us have an 内部の 24-hour 団体／死体 clock that advises us when is the best time to sleep, eat, think and 請け負う myriad other 必須の 仕事s. There are optimum タイミングs for different 団体／死体 機能（する）／行事s and 過程s.

For instance, from around 6am, your 血 圧力 starts to rise はっきりと from its low point. This is in 予期 of waking up and the need to get more oxygen and nutrients to the 組織／臓器s in 準備完了 for activity.

Your 生産／産物 of the hormone cortisol also 頂点（に達する）s first thing (between 6am and 8am) to mobilise the 団体／死体 for 活動／戦闘 by 増加するing heart 率 and the 解放（する） of gluc ose into the 循環／発行部数 for energy.

THE REASON WINTER COMMUTERS GET SO TIRED?

In 新規加入 to the colour and タイミング of light, the intensity of it is 批判的な to the タイミング of our 団体／死体 clock (see main copy below).

And the problem is that many of us are not getting enough light to 始める，決める our 団体／死体 clock. Compared with natural outside light, even in winter, 人工的な light in offices and factories is very 薄暗い.

全体にわたる, natural light is some 50 to 250 times brighter than most 人工的な light we 遭遇（する）.

Light intensity 影響する／感情s the タイミング of our 団体／死体 clock, 令状s Professor Foster

Light is 手段d in lux. Natural light is around 10,000 to 100,000 lux, depending on the 天候, compared with the 300 to 400 lux in the workplace (or 800 to 900 lux you would e ncounter の近くに to a 60 ワット bulb at home).

That’s why, no 事柄 how many years 労働者s spend on 永久の night 転換s, nearly all find their clocks don’t adapt to the 需要・要求するs of working at night. After leaving work in the morning, the night-転換 労働者 will move from the 薄暗い light in the workplace to 有望な light outside, and their clocks lock on to the brighter light signal, setting them to daytime.

People who don’t experience much natural light at all, such as nursing home 居住（者）s or 通勤（学）者s (during the short days of winter), have a different problem: they don’t get enough light to 始める，決める the clock 適切に and, just like the blind 退役軍人 示す Threadgold (see previous page), their 団体／死体 clocks drift ― and with them, the times when they sleep and wake.

Most of them will want to go to bed later and get up later.

There will also be times when they find it difficult to sleep at night, while wanting to sleep during the day.

CHEAT WITH A ‘LIGHT BOX’

To find out how 有望な (or 薄暗い) your workplace or home is compared with natural light, you can buy a lux メーター for around £20 online. You could then even buy 有望な 人工的な lights to help 始める，決める your 団体／死体 clock in the morning and see if this makes a difference to the times you sleep and wake.

One 選択 is a light box, which ふりをするs the 夜明け and dusk cycle (slowly brightening then fading) to help stabilise your 団体／死体 clock.

The main thing to look for is that they produce enough 有望な light, in the 地域 of 2,000 lux or more. Most of us need to expose ourselves to this level of light for at least 30 minutes in the morning.

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宣伝

At the other end of the day, after 7pm, your 団体／死体 気温 starts to 減少（する） in 準備 for sleep.

At the same time, growth hormone levels 増加する, 促進するing the building and 修理 of tissues. Even urine 生産／産物 slows 負かす／撃墜する at night, so we don’t have to wake and go to the loo too often.

For our 団体／死体s to 機能（する）／行事 適切に, we need the 訂正する 構成要素s ― such as hormones and proteins ― in the 権利 places at the 権利 time of day. Thousands of 遺伝子s also have to be switched on and off in a 明確な／細部 order. Enzymes, fats, carbohydrates and other 構内／化合物s have to be 吸収するd, broken 負かす／撃墜する, metabolised and produced at a 正確な time for growth, reproduction, metabolism, movement and 修理.

And to do all this, our 団体／死体 機能（する）／行事s and 過程s must be 用意が出来ている and ready at the 権利 time, guided by the 団体／死体 clock.

Without 正確な 規則, our daily cycle of activity and sleep would be in 大混乱.

Sleep is when many 必須の activities occur, 含むing memory 形式 and problem-solving by the brain. 混乱に陥れる／中断させるing our sleep pattern can lead to serious consequences for our health.

And this is where light ― or, rather, the light and dark of day and night ― comes in.

A wristwatch is of no use unless it’s ‘始める，決める’ to the 地元の time, and this is 平等に true for our 団体／死体 clock, which is 始める，決める by the daily pattern of light and 不明瞭.

In this way, our 内部の 生物学の clock and the 外部の 環境の day are 提携させるd, and this 許すs us to do the 権利 thing at the 権利 time.

All this week in the Mail, I will be explaining more about these 24-hour cycles and I will give you my step-by-step ‘prescription’ for 取り組むing tiredness.

Today, I 焦点（を合わせる） on one of the simplest but most 効果的な ways to 改善する your sleep: getting the light 権利.

‘SUPER CLOCK’ IN OUR BRAIN THAT RUNS THE SHOW

The idea of an 内部の clock is not a new one. We’ve 現実に known about these 肉親，親類d of clocks (or ‘circadian rhythms’) as far 支援する as 1729 ― not in humans, but in a 工場／植物 called Mimosa pudica.

Known to many gardeners, this 工場／植物 has delicate leaves that 倍の up at night and open during the day. ジーンズ-Jacques d’Ortous de Mairan, a French 天文学者, 観察するd that Mimosa leaves continue to show this rhythmic 倍のing and 広げるing for several days in 完全にする 不明瞭.

Over the next few hundred years, such daily rhythms, 固執するing in constant 不明瞭, were 記録，記録的な／記録するd in many 工場／植物s and animals, but it was only about 60 years ago that 研究員s began to 熟考する／考慮する these rhythms in people.

One 重要な 熟考する／考慮する 伴う／関わるd university undergraduates 存在 housed in an 地下組織の （船に）燃料を積み込む／（軍）地下えんぺい壕 in Bavaria, 孤立するd from any 外部の 環境の time cues.

Their sleep and wake cycles, 団体／死体 気温, urine 生産／産物 and other 生物学の 機能（する）／行事s were 手段d over many days and were shown to have a rhythmic pattern of about 24 hours.

And we now know that what makes these 団体／死体 clocks tick is a master clock, consisting of a pair of structures 深い within the brain, known as the suprachiasmatic nuclei.

There are clocks in the 独房s of probably every 組織／臓器 and tissue of the 団体／死体, 含むing the 肝臓, muscles, 膵臓 and fat tissue. But the suprachiasmatic nuclei 行為／法令／行動する rather like a conductor of an orchestra, 供給するing a time signal that 調整するs all the 器具s.

An 内部の clock inside our brains helps 支配（する）／統制する when we feel tired and go to sleep (在庫／株)

Without the conductor, everything 落ちるs apart and, instead of a symphony, you have a 生物学の cacophony ― and a 失敗 to do the 権利 thing at the 権利 time, not least our daily cycle of 存在 asleep or awake.

One very striking feature of circadian rhythms is that they do not run at 正確に／まさに 24 hours, and can tick a little faster or slower. In this way, they 似ている an old mechanical grandfather clock that needs a slight daily 調整 to make sure the clock is 始める，決める to the ‘real’ 天文学の day.

LOSING KIP CAN PUT YOU AT RISK OF WEIGHT GAIN?

Even just a few nights’ sleep loss can have a big 衝撃 on your emotional and brain 機能（する）／行事. You’re more likely to experience mood swings, irritability and 苦悩 ― and it can also 影響する／感情 your metabolism.

A 2004 熟考する／考慮する 設立する that getting only four hours’ sleep per night sent the glucose metabolism of healthy young men into 炉心溶融. Put 簡単に, their 団体／死体s were unable to 規制する their 血 glucose and appetite. Two gut hormones, ghrelin and leptin, seemed to play a 重要な 役割.

Sleep loss can make you more likely to experience mood swings, irritability, 苦悩 - and it 影響する／感情s your metabolism

Ghrelin is produced by the stomach and signals hunger, 特に for sugars; leptin is produced by fat 独房s and is a signal for fullness. Together, they 規制する hunger and appetite.

制限するing the sleep time of the young men under 研究室／実験室 条件s for seven days 原因（となる）d their leptin levels to 落ちる by 17 per cent and their ghrelin levels to rise by 28 per cent, and 増加するd their appetite, 特に for fatty and sugary foods.

Such sleep disruption may explain why 転換 労働者s have a higher 危険 of 負わせる 伸び（る） and type 2 糖尿病 ― and to a lesser extent why, when we’re tired, we s eek out high-calorie foods.

People who 欠如（する） sleep are also more likely to smoke and drink (probably 関係のある to 強調する／ストレス).

宣伝

WHAT HAPPENS WHEN YOUR BODY IS OUT OF SYNC?

For the suprachiasmatic nuclei master clock, this daily 調整 is 成し遂げるd by the cycle of light and 不明瞭. Without this resetting, the 内部の day would soon drift and be out of sync with the 環境の day/night cycle.

Many of us have experienced a 厳しい form of this mismatch in the form of jet lag.

After travelling across 多重の time zones, our 団体／死体 clock and the 地元の time do not match, and we want to sleep and eat at the wrong times. But we do 結局 catch up with the new time zone. The question is: How?

I cannot 強調 enough that a clock is of no use unless it is 始める，決める to 地元の time ― and for most 工場／植物s and animals, the signal that 提携させるs the 内部の day to the 外部の world is light, and 特に light at sunrise and sunset.

This is evident from the experiences of people who have lost their sight, who drift through time, with periods when they get up and go to bed at the 訂正する hours, and other times when they want to sleep, eat and be active at the wrong time of day.

示す Threadgold, 52, a former 兵士 supported by the charity Blind 退役軍人s UK, is a typical 事例／患者. Twenty years ago, he was left blind by an 事故 at work.

While he has adapted to his sight loss, he’s struggled with sleep, because without the cues of light and 不明瞭, his 団体／死体 clock drifts. He starts by 落ちるing asleep around 10pm and waking around 5am, but the time he 減少（する）s off then 転換s by an hour every day or so.

At some point in the month, he’s unable to sleep at all in the night. A few weeks later, he’s asleep at 10pm again. (I’m working with Blind 退役軍人s UK to help people like 示す ― and am 希望に満ちた that we will soon have a 麻薬 that will be able to ‘始める，決める’ the 団体／死体 clock, fooling it into believing it has seen light, and 回復するing a sense of time.)

As to how the 団体／死体 clock 作品, my team and I recently made an exciting 発見.

The light signals that the suprachiasmatic nuclei master clock rely upon are received 経由で light-極度の慎重さを要する 独房s (called photoreceptors) in the 注目する，もくろむ. There are two types of photoreceptor, 棒s and 反対／詐欺s, used for 見通し.

For １０年間s it was thought that these also （悪事，秘密などを）発見するd sunrise and sunset to 規制する the 団体／死体 clock. But we have discovered a third group of photoreceptors, called photosensitive retinal ganglion 独房s, and these are 批判的な for setting the clock.

MY SIMPLEST, MOST EFFECTIVE SLEEP TIP

These photosensitive retinal ganglion 独房s are most 極度の慎重さを要する to blue light (the type that is emitted in daylight and from many 電気の 装置s) and seem to be ‘tuned’ to （悪事，秘密などを）発見する the blue light of 夜明け and dusk.

When we think of sunrise and sunset, our image is of a red rising or setting sun ― but in fact, above the sun it is blue.

Indeed, there’s 現実に more blue light at sunrise and sunset than at any other time of the day.

This does not mean that the photosensitive retinal ganglion 独房s （悪事，秘密などを）発見する only blue light, but it takes more 非，不，無-blue light to get the same 影響 on the 団体／死体 clock ― so （危険などに）さらす to natural light in the hours after sunrise and before sunset will adjust the clock, but much いっそう少なく 効果的に.

（危険などに）さらす to natural light in the hours before and after sunset will adjust the 団体／死体 clock (在庫／株)

So, what does this all mean?

簡単に, that the most 効果的な way to 始める，決める your 団体／死体 clock is to experience natural light 30 to 60 minutes after sunrise and before sunset.

Easier said than done, you might think, 特に in the sub-無 mornings of winter. But while this 夜明け light is the most 効果的な, light （危険などに）さらす later in the day, until noon, will also help ― it’s just that sooner after sunrise is better.

I’m certainly the last person to get up at 夜明け to 先触れ（する） the sun, but when I do wake up, the first thing I do is open the curtains; I’ll also have my breakfast and morning coffee sitting by the window at home or at work.

Other tricks you could try 含む getting off the bus, and 特に the Tube, a stop 早期に to walk in the natural daylight.

It doesn’t 事柄 if it’s 曇った because the photosensitive retinal ganglion 独房s ‘追加する up’ the light they receive; it might take longer than on a 有望な day to get the message, but the light message is received 結局.

BLUE LIGHT FROM DEVICES I S NOT THE ISSUE

As the photosensitive retinal ganglion 独房s are most 極度の慎重さを要する to blue light, 製造業者s have produced lights 濃厚にするd with blue light that can be used to artificially 始める，決める your 団体／死体 clock when you can’t experience the natural 夜明け and dusk cycle.

類似して, much has been made of 減ずるing ‘blue light’ from 装置s such as 動きやすい phones and laptops (using red filters on 審査するs, for instance) to 避ける 延期するing the 団体／死体 clock and 原因（となる）ing sleep problems.

This may sound like heresy but, as I will explain in greater 詳細（に述べる） later this week, it’s not the light emitted from these 装置s that’s the problem, as there’s not enough of it to have real 影響.

The real 問題／発行する is staying up half the night using the 装置 ― and getting いっそう少なく sleep.

ARE YOU A LARK OR AN OWL??

It’s not only the light that 事柄s: your 団体／死体 clock タイミング is also partly 負かす／撃墜する to your parents. Have you ever asked yourself why is it that you like to go to bed 早期に and your spouse does not?

Thanks to 研究 by three U.S. scientists who 株d the Nobel Prize in 2017, we now know how our ‘clock’ 遺伝子s and the proteins they produce 生成する the 団体／死体 clock.

Slight differences in these clock 遺伝子s have been linked to whether we are a ‘lark’ (a morning person) or an ‘フクロウ’ (an evening person).

遺伝子s can also 支配（する）／統制する the 団体／死体 clock, deciding whether you are a lark or an フクロウ

Most of the 全住民 are 現実に 中立の types, which means they 概して 適合する with the social norm ーに関して／ーの点でs of sleep and wake times.

Morning types prefer to go to sleep 早期に and get up earlier than the social norm, and it seems that they have faster 団体／死体 clocks.

By contrast, evening types, or ‘フクロウs’, have slower 団体／死体 clocks and prefer to go to bed later and sleep in for longer compared with the societal norm.

So, by their 出資／貢献 to our 遺伝子s, our parents are still telling us when to get up and when to go to bed!

Our 団体／死体 clock type (or chronotype) may be 相続するd, but it’s 影響する／感情d by a number of factors, 含むing age and light. And you can cheat the system. For instance, if you’re an フクロウ but need to get to work 早期に, make sure you get plenty of either natural or 人工的な light in the morning (and 避ける light at dusk), which will 前進する the clock, making you get up earlier and go to bed earlier.

If you’re a lark and want to be more like the 残り／休憩（する） of society, get evening light (and 避ける morning light), which will 延期する the clock, making you go to bed later and get up later.

宣伝

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