Let’s say you need to wake up by 7 am to get to work on time. You set your first alarm for 6：30 am， your second at 6：45 am and your third at 6：55 am. And you throw in 7：05 am just to be cautious.

“Hitting the snooze button at a time does the same thing. It’s satisfying in the moment to hit the snooze button but it does actually undermine the sleep quality，” said Dr Brandon Peters， a neurologist and sleep medicine physician from the US.

For the last hours of sleep， people usually go in and out of the fourth and last stage of the sleep cycle， known as rapid-eye-movement sleep. This stage is particularly important for memory processing and creative thinking， he added. Having that stage of sleep fragmented could impact the brain function.

He recommends setting one alarm， allowing for deep sleep to continue uninterrupted until you need to wake up in the morning.

假設(shè)你需要早上7點(diǎn)起床以確保準(zhǔn)時(shí)上班，你設(shè)置了三個(gè)鬧鐘，分別在早上6：30、6：45和6：55，以確保自己能夠按時(shí)醒來(lái)。以防萬(wàn)一，你還加了一個(gè)早上7：05的鬧鐘。

美國(guó)的神經(jīng)學(xué)家兼睡眠醫(yī)學(xué)醫(yī)生布蘭登·彼得斯博士說(shuō)：“每次按貪睡按鈕也會(huì)產(chǎn)生同樣的結(jié)果。按下貪睡按鈕，這在當(dāng)時(shí)會(huì)讓人感到滿足，但實(shí)際上破壞了睡眠質(zhì)量?！?/p>

在睡眠的最后幾個(gè)小時(shí)里，人們通常會(huì)進(jìn)入并退出睡眠周期的第四個(gè)也是最后一個(gè)階段，即快速眼動(dòng)睡眠。他補(bǔ)充說(shuō)，這個(gè)階段對(duì)記憶處理和創(chuàng)造性思維特別重要。這個(gè)階段的睡眠如果被打亂，可能會(huì)影響大腦的功能。

他建議設(shè)置一個(gè)鬧鐘，讓深度睡眠繼續(xù)進(jìn)行，直到你早上需要起床為止。

“If you have to wake up at 7 am， and the alarm starts at 6 am， you are getting an hour of bad-quality sleep，” said Dr Alicia Roth， a clinician from the US. While setting just one alarm is best， it might be hard to wake up to only one after using multiple alarms as your safety net， she added.

How to wake up to one alarm？

It is important to wake up and go to sleep around the same time each day， said Dr Cathy Goldstein， a sleep medicine physician in the US. “If you’re somebody who sleeps really well from 3 am to noon， and that’s how you sleep on the weekends， but on one Monday morning， you have to wake up at 6 am to commute， that will be hard，” she said. “That’s earlier than your biology is prepared to wake up， and it’s going to be very difficult to get up.”

Goldstein recommends shifting bedtime 30 minutes earlier every few days， or an hour earlier once a week for those looking to change their biological clocks. Avoiding harsh lights and limiting screen time up to four hours before bed can also help promote the body’s natural melatonin production， she added.

美國(guó)的臨床醫(yī)生艾麗西亞·羅斯博士說(shuō)：“如果你必須在早上7點(diǎn)醒來(lái)，而鬧鐘在早上6點(diǎn)響起，那么你將獲得一個(gè)小時(shí)的低質(zhì)量睡眠?！彼a(bǔ)充說(shuō)，雖然設(shè)置一個(gè)鬧鐘是最好的，但在使用多個(gè)鬧鐘作為安全保障之后，可能很難只用一個(gè)鬧鐘就醒來(lái)。

如何用一個(gè)鬧鐘喚醒自己？

美國(guó)的睡眠醫(yī)學(xué)醫(yī)生凱西·戈德斯坦博士說(shuō)，每天在同一時(shí)間醒來(lái)和入睡很重要?！叭绻闶悄欠N從凌晨3點(diǎn)睡到中午的人，而且周末你也這樣做，但是在某個(gè)周一的早上，你必須早上6點(diǎn)起床去上班，那將會(huì)很困難。”她說(shuō)，“這比你的生物鐘準(zhǔn)備好的起床時(shí)間要早，所以起床會(huì)非常困難?！?/p>

戈德斯坦建議那些想改變生物鐘的人，每隔幾天就將就寢時(shí)間提前30分鐘，或者每周提前一個(gè)小時(shí)。她補(bǔ)充說(shuō)，避免強(qiáng)烈的光線和在睡前四小時(shí)內(nèi)限制手機(jī)等設(shè)備的使用時(shí)間也有助于促進(jìn)人體自然分泌褪黑素。

Word Bank

undermine /'?nd?'ma?n/ v. 破壞；使逐步減少效力

uninterrupted /'?n'?nt?'r?pt?d/ adj. 不間斷的；持續(xù)不斷的

harsh /hɑ??/ adj. 強(qiáng)烈刺眼的