Karoshi is the Japanese term for “death from overwork”, literal occupational sudden death– the major medical causes being heart attack and stroke due to stress at work and often without previous signs of illness. In a country where employees were known to work 12+ hours a day six or seven days of the week and often working unpaid overtime hours, it doesn’t come as a surprise that Japan is one of the few countries that reports Karoshi as a separate category in national statistics. Japan broke a record in the financial year of 2006-07 when around 355 workers fell ill from overwork, and of them, 147 typically died of heart attack or stroke. The statistic was Japan’s highest figure, a 7.6% increase from the previous year in spite of government efforts to cut hours. But with Japanese employees putting in an average of 1,780 hours annually, not including unpaid overtime, the campaign to pre-empt karoshi would have to overcome some big obstacles.

Kenichi Uchino, a 30 year old Toyota employee, shortly before he died, collapsed at work at 4 am after more than 80 hours of overtime a month for six months, told his wife he was happiest when asleep.

From the Scientific American under the article “Can Work Kill?”:

“A 1998 survey of 526 Japanese men, aged 30 to 69, supported the idea that long working hours can be hazardous to a man’s health. The subjects of the study included men who had been hospitalized with a heart attack as well as healthy men of similar ages and occupations. The results were striking: Men from both groups who put in more than 11 hours of work on an average day were 2.4 times more likely to have a heart attack than were men who worked “just” seven to nine hours a day.”

Let’s take Sweden: In 1996 a Swedish study explored not just working hours and its correlation to health, but working conditions. More than 12,500 employed men over a period of 14 years were observed and evaluated by the psychological and physical demands of each individual man’s occupation. Age, exercise habits, smoking history, medical history, educational level and social class of each were collected. The results? Those with low control over the demands of their jobs were 1.8 times more likely to die from heart disease than those with more control were. Those with low-level social support from co-workers were 2.6 times more vulnerable to cardiovascular death.

2,465 Danish bus drivers were observed in an earlier study. The intensity of traffic on the drivers’ routes were linked to a two-fold increase in the risk of heart attack and death. Lack of social support only served to compound the problem. A seven-year study of 500 Swedish men implicated job strain as a predictor of mortality–high demands and low control combined to explain this effect. A related Italian study of 99,029 railway workers found that the particular combination of high job responsibility and minimal physical activity was associated with an increased risk of heart attack.

An American study assessed stress, personality, and psychological strain by questionnaire among 73 males with a mean age of 23 years old, 73% of whom worked full-time. Anxiety was positively associated with role ambiguity in the work place, as well as depression and resentment. Anxiety was also positively related to heart rate, the relationship between anxiety and work load greatest among Type A personalities.

High mental demands, low personal control and inadequate social support are the particularly worrisome factors of how overwork exacts its toll on the mind and body, and by extension, longevity.

Though more research is required to verify these observations, we do know that mental stress heightens adrenaline and cortisone blood levels, two of the so-called stress hormones while psychological stress raises heart rate and blood pressure. It can also induce arrhythmia, or abnormal heart pumping rhythm. Platelets in the blood can also be activated by stress, triggering clots that can block diseased coronary arteries.

Perhaps one of the better approaches to work can be found in France, where despite comparatively short workweeks, French employees regularly top productivity surveys. Though less time is spent at the office than their American and Japanese counterparts, when they are in the office, their time is used more efficiently. Perhaps cutting the number of hours you give yourself to complete tasks will help you get them done in a more timely manner, getting you home to your family, friends and mental “happy place” faster. As the French say: À Votre Santé!




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