A three-day-week gets the best performance from workers aged over 40, a study has found.

一项研究发现，40岁以上的人如果每周上三天班，工作表现最佳。

Researchers found the cognitive performance of middle-aged people improved as the working week increased up to 25 hours a week.

研究人员发现，当中年人每周工作时间达到25小时，认知表现将有所改善。

However, when the week went over 25 hours, overall performance for the test subjects decreased as "fatigue and stress" took effect.

然而，如果每周工作时间超过25小时，受试者的整体表现则将恶化，因为“疲劳和压力”开始产生影响。

The report, which was published in the Melbourne Institute Worker Paper series, invited 3,000 men and 3,500 women in Australia to complete a series of cognitive tests while their work habits were analysed.

发表在《墨尔本研究院工人报》的这篇研究报告邀请了澳大利亚的3000名男性和3500名女性来完成一系列认知测试，同时分析他们的工作习惯。

It was found those working 25 hours a week performed best while those working 55 hours a week showed results worse than retired or unemployed participants.

研究发现，每周工作25小时的人表现最佳，而每周工作55小时的人的测试成绩比那些退休或待业的人还糟。

One of the three authors, Professor Colin McKenzie from Keio University told the Times: "Many countries are going to raise their retirement ages by delaying the age at which people are eligible to start receiving pension benefits. This means that more people continue to work in the later stages of their life.

该研究报告的三位作者之一、来自日本庆应义塾大学的科林•麦肯齐教授告诉《泰晤士报》说：“许多国家都预备提高退休年龄，让人们延迟领取养老金。这意味着更多人在中晚年还要继续工作。

"The degree of intellectual stimulation may depend on working hours. Work can be a double-edged sword, in that it can stimulate brain activity, but at the same time long working hours can cause fatigue and stress, which potentially damage cognitive functions.

“智力被激发的程度可能取决于工作时长。工作是一把双刃剑，既能够刺激大脑活动，同时过长的工作时间也会导致疲劳和压力，并有可能损害认知功能。

"We point out that differences in working hours are important for maintaining cognitive functioning in middle-aged and elderly adults. This means that, in middle and older age, working part-time could be effective in maintaining cognitive ability."

“我们指出了不同工作时长的区别所在，这对于保持中老年人的认知功能具有重要意义。这意味着，在中晚年，从事兼职工作将能有效地保持认知能力。”

The research comes amid moves to edge the British state pension age closer to 70.

研究发布正值英国计划将法定退休年龄提高到将近70岁。

Currently for someone born in 1989, a state pension begins at the age of 68.

根据目前的法规，1989年出生的人要到68岁才能领到养老金。