The reasons why the remarkable gaps exist are subject to debate. This author, however, believes that there are two main factors; unpaid overtime work, which can be called illegal, and the overtime work by the employees on the position of middle management, which cannot be called illegal.

The most serious injuries of health brought on is death from overwork, so called “karoshi.” According to the official classification of disease, the main cause of “karoshi” is cardio vascular disease, especially among the middle-aged and older male employees and self-employed.

# Overwork and health Injuries

## ABSTRACT

The aim of this study is to analyze the problems of overwork in Japan in connection with health injuries, and to propose concrete measures for improvement.

I. Basic Recognition on the overwork and the health injuries.

A. Changes in the quantity of workload

Looking at the working hours per annum as an indicator of the quantity of workload, there is a remarkable tendency that has continued since the middle of the 1960s. The observed tendency is quite different between male and female employees. On the one hand, the females' hours worked has continued to decline for the whole period. On the other hand, however, the males' hours worked began to increase in the mid 1970s, when Japanese companies struggled to overcome the serious recession brought about by the first oil crisis, with the slogan of the "stripped down management." This "stripped down management" has been maintained in the phases of the recovery and expansion of the business cycles. As a result, the average hours worked for male employees reached a peak level of 2,700 hours in 1988, which is as high as in the latter half of 1960s. The male employees' hours worked, after hitting the peak level, began to decrease in step with a downward trend of business conditions, but still remaining a high level of 2,500 hours a year in 1992. Meanwhile, the number of employees working more than 3,100 hours a year, sharply increased and occupied in 1988 a share of one out of four, which is almost the same in the middle of 1960s, and showing in 1992 a share of one out of six.

The statistical facts illustrated above are based on the Labour Force Survey, published by the Statistical Bureau of the Management and Coordination Agency. The hours worked are also reported by the Monthly Labour Survey, published by the Ministry of Labour.

The former statistics collects statistical information from households, the latter from companies. There are significant gaps in the length of hours worked between the two statistics. That is, the hours worked per year reported in the Monthly Labour Survey, which is commonly used, are smaller by about 400 hours for the male employees and about 200 hours for the female employees, than those reported in the Labour Force Survey.

### B. Changes in the quality of workload

Owing to automation, computerization and various kinds of technological innovation, both at factories and offices, the physical heaviness of the workload, for instance, in terms of calories needed, has been mitigated. In the process of pursuing higher efficiency, however, occupational stress has inevitably worsened. Night shifts and all-day services have also been increasing. These changes in the quality of workload are likely to create unfavorable effects on the health conditions of workers.

C. Relationship between overwork and health injuries

Except for the death from overwork, various kinds of disease, which are generally referred to as the