Australian Workers
Office workers head to Flinders Street Station in central Melbourne February 10, 2011 Reuters/Mick Tsikas

Japanese work experts have recommended a 40-hour work week for Australians in their 40s. By reducing their working week to just three days, mid-age Aussie workers would be at their peak performance.

The recommendation was based on an analysis of employment habits and cognitive test results of 3,000 male and 3,000 female Australian workers aged 40 and above, reports Times. Working only part time, instead of the regular 80-hour weekday, provides the best balance to keep them mentally stimulated without causing them too much exhaustion and stress.

Among the cognitive tests the participants did were to read words aloud, recite a list of numbers backward and connect numbers and letters in a particular pattern while under time pressure. Those who worked about 25 hours a week often got the best scores, the unemployed scored 18 percent lower on the reading test and 20 percent lower on the backward numbers test.

The results, according to Keio University professor of economics Colin McKenzie, indicate too much or too little work results in cognitive performance decline. The results of the study, published in a working paper series of the Melbourne Institute, comes at a time that a number of western countries moved their retirement age past 70 years old.

The professor notes that degree of mental stimulation is linked with the number of working hours in middle-aged and elderly adults. The study concludes that for older male workers, the ideal to keep cognitive function is to work 25 to 30 hours a week, while for older women workers, it would be slightly shorter at 22 to 27 hours a week.