Long work hours have been known to have an association with cardiovascular disorders, specifically coronary artery disease.
A recent meta-analysis studies the role of work hours and stroke in 528,908 stroke-free men and women and included 25 studies from 24 cohorts in Europe, the USA, and Australia. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2815%2960295-1/abstract
Follow-up was a mean of 8.5 years. Compared to standard hours (35-40 hours/week) working long hours (≥55 h per week) was associated with an increase in risk of incident coronary heart disease and incident stroke (1.3 times increased risk or 33%) . The association with stroke was stronger and ‘dose dependent’ meaning the association was strongest for those working > 55 hours and less for 49-54 and 41-48 hours/week.
The authors point out that “sudden death from overwork is often caused by stroke and is believed to result from a repetitive triggering of the stress response” and physical inactivity indicated by sedentary work.
Problem with the study is that the analysis included many uncontrolled, observational studies some of whom were not even peer reviewed. Also risk factors for stroke and CAD were not studied. Working 50 hours as a secretary may not have the same stress as a company CEO or harried physician.
In Gallup surveys in 2013 and 2014, 40% of full-time American workers reported working at least 50 hours weekly, and half said they usually work more than 40 hours. (http://well.blogs.nytimes.com/2015/08/19/researchers-link-longer-work-hours-and-stroke-risk/?_r=0).
I imagine a trial, which is properly controlled for all possible variants would be practically impossible to do. In the meantime, as Steve Jobs said “"Your time is limited, so don't waste it living someone else's life."!!