Once again, science supports what your grandmother told you: A good night's sleep helps your body fight a cold.

    People who averaged fewer than seven hours of sleep per night in the weeks before being exposed to the cold virus were nearly three times as likely to get sick as those who averaged eight hours or more, a new study found.

    Researchers used frequent telephone interviews to track the sleep habits of more than 150 men and women aged 21 to 55 over the course of a few weeks. Then they exposed the subjects to the virus, quarantined them for five days and kept track of who got sick.

    Besides sleeping more, sleeping better also seemed to help the body fight illness: Patients who fared better on a measure known as 'sleep efficiency' - the percentage of time in bed that you're actually sleeping - were also less likely to get sick.

    The results held true even after researchers adjusted for variables such as body-mass index, age, sex, smoking and pre-existing antibodies to the virus.

    Like your grandmother, the researchers aren't exactly sure why sleeping better makes you less likely to develop a cold. But they do take a stab at the answer: 'Sleep disturbance influences the regulation of proinflammatory cytokines, histamines, and other symptom mediators that are released in response to infection.' In plain English, maybe tossing and turning when you're infected with the cold virus contributes to the symptoms that define a cold.

    The researchers were based at Carnegie Mellon, the University of Pittsburgh and the University of Virginia, and the study was funded by the National Institutes of Health.

    科學(xué)調(diào)查又一次證實(shí)了老祖母?jìng)兊恼f(shuō)法：一夜好睡眠，感冒擋在門(mén)外面。

    一項(xiàng)新的研究發(fā)現(xiàn)，那些在接觸感冒病毒前的一周內(nèi)平均每晚睡眠時(shí)間不足7小時(shí)的人患病幾率是睡眠不少于8小時(shí)的人的近3倍。

    研究人員通過(guò)經(jīng)常性的電話訪問(wèn)跟蹤了150多名21-55歲年齡段的人（有男有女）幾周內(nèi)的睡眠習(xí)慣。然后讓這些研究對(duì)象接觸感冒病毒，隔離5天之后，看看哪些人患上了感冒。

    除延長(zhǎng)睡眠時(shí)間外，提高睡眠質(zhì)量看起來(lái)也有助于人體抵抗疾病。那些在"睡眠效率"評(píng)測(cè)中表現(xiàn)較好的病人患病的幾率也較低。"睡眠效率"是受訪者睡下后實(shí)際"睡著"的時(shí)間所占的百分比。

    即便是在研究人員將身高體重指數(shù)（BMI）、年齡、性別、是否吸煙以及是否早有抗體等因素考慮進(jìn)來(lái)進(jìn)行調(diào)整之后，這個(gè)結(jié)論仍然成立。

    和老祖母?jìng)円粯�，研究人員也不能肯定為什么睡得好能降低患感冒的幾率。不過(guò)他們猜測(cè)原因可能是：睡眠不良會(huì)影響人體對(duì)促炎細(xì)胞因子、組胺和其他為應(yīng)對(duì)病毒感染而釋放的癥狀調(diào)節(jié)因子的調(diào)節(jié)。說(shuō)白了，就是染上感冒病毒后睡覺(jué)時(shí)的輾轉(zhuǎn)反側(cè)可能是造成感冒癥狀的原因之一。

    這項(xiàng)研究是由來(lái)自卡內(nèi)基梅隆大學(xué)、匹茲堡大學(xué)和弗吉尼亞大學(xué)的人員完成的，研究經(jīng)費(fèi)由美國(guó)國(guó)家衛(wèi)生研究院（National Institutes of Health）提供。