Panel data analysis on the impact of working hours on employee subjective health in Japan

Abstract

In recent years, long working hours have become a social problem, causing workers to develop cerebrovascular diseases and mental illnesses, and in some cases even taking their own lives. The government advocates the reform of the way of working and revised the labor-related laws in April 2019, and implemented a measure to prevent overwork by changing the upper limit of overtime work from the previous system of “practically no upper limit” to an upper limit of less than 100 hours per month for a single month and an average of 80 hours per month for multiple months, with penalties for exceeding the upper limit.

In this study, with the aim of verifying the validity of the government’s upper limit on overtime, we analyzed the relationship between working hours and the subjective health, using panel data on the number of working hours during which the subjective health deteriorates. As a result, it became statistically clear that the subjective health of workers deteriorates when their monthly working hours exceed 210 hours. 210 hours of monthly working hours is equivalent to 50 hours of overtime work and the upper limit of 100 hours of overtime work in a single month and an average of 80 hours per month in multiple months established in April 2019 is insufficient from the perspective of preventing health problems among workers. In addition, the number of working hours by which a worker’s subjective health deteriorates differs depending on gender, and it has become clear that the threshold for women is low. Meaningful implications were obtained in terms of the utilization of women while ensuring their health in the future.