研究稱工作8小時可能導致智商下降，5小時最佳

Working more than 25 hours a week could be negatively affecting the intelligence of employees over age 40, according to a study from researchers for the Melbourne Institute of Applied Economic and Social Research in Australia. After conducting reading, pattern and memory tests on more than 6,000 workers, the team determined that working 25 hours a week was the ideal amount of time for cognitive functioning.

Working fewer than 25 hours was detrimental to the brain’s agility, while working excessively long hours could cause fatigue or stress, also damaging the brain’s functional abilities.

Age 40 is somewhat of a turning point for the brain. Our "fluid intelligence," or how well we process information, begins its decline around the age of 20, while "crystallized intelligence," or the ability to use knowledge and experiences, deteriorates starting around age 30. By the time we turn 40, our performance in memory tests and pattern recognition exercises tends to dip off.

The researchers are looking into the effect of caretaking on cognitive function in middle age. By age 40, many employees are also taking care of children or a parent or both, creating a job on top of a job. The typical caregiver in the U.S. is a 49-year-old employed female, who spends more than 24 hours taking care of others, the BBC reported. Another factor could be sleep deprivation; high achievers often claim that they can work well on very little sleep.

The study noted that the effect of excessive work hours affected both genders equally.

澳大利亞墨爾本應用經(jīng)濟暨社會研究所(Melbourne Institute of Applied Economic and Social Research)的一項研究顯示，每周工作超過25個小時，會對40歲以上員工的智力產(chǎn)生負面影響。研究團隊對超過6,000名員工進行閱讀、模式和記憶測試之后確定，每周工作25小時，對于認知功能是最為理想的。

工作時間少于25小時不利于大腦的靈敏度，而每周工作時間過長，則會導致疲勞或壓力，損壞大腦的功能。

40歲是人腦的一個轉(zhuǎn)折點。我們的“流動智力”或處理信息的能力，在20歲左右開始下降，而“晶體智力”或使用知識與經(jīng)驗的能力則在30歲左右開始衰退。到40歲，人類在記憶力測試和模式識別中的表現(xiàn)會出現(xiàn)下滑。

研究人員正在研究照料他人對中年人認知功能的影響。到了40歲，許多員工還要照顧孩子或一位甚至兩位老人，形成了凌駕于職業(yè)之上的工作。據(jù)BBC報道，美國的家庭看護者通常為49歲的職業(yè)女性，她們要花超過24小時來照顧其他人。另外一個因素可能是睡眠剝奪;許多取得高成就的人往往會聲稱，他們只需要非常少的睡眠，也可以做得很好。

研究顯示，工作時間過長對男性和女性的影響沒有區(qū)別。