Restoring Balance: The Effect of Work Hour Limits on Employee Health
Park, K. F., Yim, J., Kim, Y. J., Park, T.-Y., Kim, M.
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Cutting South Korea’s workweek from 68 to 52 hours improved employee health on average — but the gains flowed to higher-income and male workers, while the lowest-income quintile saw none or even harm.
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This paper examines whether statutory limits on work hours causally improve employee health. We exploit South Korea’s 2018 reform, which reduced the maximum workweek from 68 to 52 hours while exempting certain transportation and healthcare industries, as a quasi-natural experiment. Using administrative health screening data from the National Health Insurance Service—comprising over 1.23 million employee-year observations with objective clinical biomarkers—we estimate difference-in-differences models comparing employees in treated industries to those in exempt but otherwise comparable sectors. We find that the reform significantly reduced body mass index (BMI), fasting blood sugar (FBS), and liver enzyme levels (SGOT and SGPT) among treated employees relative to controls. These improvements were accompanied by reduced drinking frequency and increased exercise frequency, consistent with lower chronic stress and expanded opportunities for recovery, respectively. However, the benefits were concentrated among higher-income and male employees; the lowest-income quintile experienced no improvement and even adverse effects on liver function. These findings indicate that work hour regulations can improve population health, but that their distributional consequences—particularly for economically vulnerable workers—warrant careful attention in policy design.