From The Washington Post:
For decades now, the modern worker has been urged to slow down, chill out, de-stress. Doctors link long shifts and on-the-job anxiety to high blood pressure, heart disease, depression and stroke. Many believe the consequences can be fatal. In Japan, the government compensates families who lose loved ones to employment-related exhaustion or suicide. The Japanese call this phenomenon karoshi, or death by overwork.
Yet, so far, the connection between job strain and bad health has mostly been correlational — we haven’t known if stressful jobs directly cause our health to deteriorate. Surveys show that people who work more are more likely to suffer from hypertension and more likely to experience a stroke. The plausible biological explanation: Both of these health problems are symptoms of stress and sleep deprivation.
But what if it wasn’t the job’s fault? What if naturally obsessive or anxious people gravitate to occupations where they are forced to work too much? What if the people who volunteer for overtime only do it because they need the money to solve some other crisis in their life? The connection between bad health and overwork, as common-sense as it seems, is cloudy.
Recently, economists at Purdue and the University of Copenhagen made a clever attempt to clear up the question. They looked at Danish manufacturing companies where overseas sales increased unexpectedly due to changes in foreign demand or transportation costs between 1996 and 2006. These constituted a set of natural experiments. At firms where exports spiked, there was suddenly a lot more work to do, a lot more things to sell. This put the squeeze on employees, who became measurably more productive — but also started to suffer more health problems.
“The medical literature typically finds that people who work longer …