Study: Long working hours increase deaths from stroke and heart disease "Working 55 hours or more per week is a serious health hazard," WHO said. Ryan Beard/Scripps National News Team and last updated 2021-05-17 11:43:14-04 GENEVA, Switzerland â As companies merged or were acquired over the last 10 to 20 years, millions of workers were laid off, furloughed, or downsized workers. Still, one thing remained: long working hours for those who survived the cuts. But a new study from the World Health Organization says those long working hours may be sending many to an early grave. According to the WHO study, âlong working hours led to 745,000 deaths from stroke and ischemic heart disease in 2016.â The number represented an overall 29 percent increase in deaths since 2000 in the joint study from the World Health Organization and International Labour Organization. The study found that in 2016, 398,000 people died from stroke and 347,000 from heart disease as a result of working at least 55 hours a week.