In the largest study of its kind to date, researchers have revealed that a considerable part of all deaths from ischemic heart disease and stroke worldwide is caused by working long hours .
Beware of Karoshi
What can we do to live longer until science can produce a suitable solution to aging? One of the answers seems to be “work less”. Working fewer hours means more time for potentially more enjoyable and fulfilling activities, and it can greatly benefit your health.
This is a common wisdom, of course, immortalized in idioms and proverbs in many languages, but the world seems to be paying little attention. The average working time was in a steady decline worldwide over the second half of the 20th century, but this trend either stopped or reversed itself in many countries during the 21st century. This study has found that the percentage of people working long hours increased substantially between 2010 and 2016.
During these years, we also saw some horrifying anecdotal evidence that long working hours can kill, such as the story of the Merrill Lynch intern Moritz Erhardt, 21, who was found dead in his shower after working for 72 hours straight. Erhard had epilepsy that could have been exacerbated by the enormous stress of working three days non-stop. Although Erhard’s death was never directly linked to overwork, in the aftermath of this event, Goldman Sachs capped its interns’ working days at 17 hours – which is still very far from normal. Since then, the infamous overworking culture in the financial sector has been implicated in several suicides, mostly of young employees.
In Japanese, “Karoshi” means sudden death from overwork. The term was coined in 1978, but the first incident that brought this phenomenon to the nation’s attention was the fatal stroke of a 29-year-old clerk a decade earlier. Karoshi deaths skyrocketed during Japan’s economic boom in the 80s, with this pattern repeating itself all over the world; it seems to be that rising prosperity exacerbates overwork. According to the study, in 2016, 8.9% of the global population was working long hours. Tellingly, Southeast Asia and Eastern Pacific, the region that includes Japan, are the most affected.
Most victims of overwork are men: they work more and suffer more from the consequences, and the study found that 72% of deaths had occurred among males. Sadly, the researchers were not able to account for the immense amount of unpaid work that women perform out of their regular work hours. Age is also a factor, with most of the deaths being recorded among people aged 60-79 who had worked for 55 hours or more per week between the ages of 45 and 74 years.
750,000 deaths a year
In this largest study of its kind to date, the researchers explored just two health outcomes in connection to overwork: deaths from ischemic heart disease and stroke. A meta-analysis of dozens of studies led them to conclude that long working hours (55 hours a week or more) were responsible for 745,000 deaths from these two factors in 2016 alone. Of these, 398,000 deaths were from stroke and 347,000 from heart disease. Between 2000 and 2016, the number of deaths from heart disease due to working long hours increased by 42%, and from stroke by 19%. Of all deaths from ischemic heart disease and stroke in 2016, 3.7% and 6.9% respectively were attributable to overwork.
Needless to say, heart disease and stroke are not the only possible health consequences of working long hours . Overwork is thought to be responsible for about one-third of the total work-related disease burden – more than any other factor.
The researchers suggest two pathways that can cause health problems due to overwork. The first is the direct effect of psychosocial stress that leads to the release of stress hormones. It can cause dysregulation of the cardiovascular system and even structural harm, such as lesions. The second pathway involves behavioral responses to stress, such as tobacco and alcohol use, overeating and an unhealthy diet, physical inactivity, and impaired sleep quality.
This last factor, sleep deprivation, is quickly emerging as a major health hazard . Not only can it result in overeating and obesity due to food cravings, sleep deprivation also increases the risk of heart disease by 48%, of colorectal cancer by 36%, and of Type 2 diabetes threefold. Usually, we focus on the health aspects of longevity, but a car crash can also be abruptly detrimental to long life. Sleep deprivation causes around 6,000 fatal car accidents a year in the US alone.
The study was conducted on data before the COVID-19 pandemic, which has greatly accelerated the transition towards remote work. It remains to be seen how much of a threat this is. On one hand, remote work decreases commute time, but on the other, it contributes to the blurring of the boundaries between work and leisure.
The drive to overachieve is understandable, but the culture of workaholism exacts a heavy price. As disastrous health consequences of working long hours become clearer, more people might want to reconsider their priorities. Stepping away from overworking can considerably lessen the disease burden in the population and contribute to a longer lifespan and healthspan.
 Pega, F., Náfrádi, B., Momen, N. C., Ujita, Y., Streicher, K. N., Prüss-Üstün, A. M., … & Woodruff, T. J. (2021). Global, regional, and national burdens of ischemic heart disease and stroke attributable to exposure to long working hours for 194 countries, 2000–2016: A systematic analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury. Environment International, 106595.
 Sparks, K., Cooper, C., Fried, Y., & Shirom, A. (2018). The effects of hours of work on health: A meta-analytic review. In Managerial, Occupational and Organizational Stress Research (pp. 451-468). Routledge.
 Altevogt, B. M., & Colten, H. R. (Eds.). (2006). Sleep disorders and sleep deprivation: an unmet public health problem.