Workers Health & Safety Centre

Long work hours increases risk of stroke, study warns

A recent study found people who regularly work long hours had a higher risk of stroke, especially those who’ve done so for 10 years or more.

This research, published in the American Heart Association’s journal Stroke, analyzed data on the working hours of more than 140,000 people in France.

The researchers defined long work hours as working more than 10 hours for at least 50 days a year. They found the 42,000 participants who reported working long hours had a 29 per cent greater risk of stroke. The risk increased to 45 per cent for the more than 14,000 who reported working long hours for 10 years or more.
 
A total of 1,224 of the study participants suffered strokes.
 
Participants were between the ages of 18 and 69. Those who had previously suffered strokes before regularly working long hours and those with part-time employment were excluded from the study.
 
“The association between 10 years of long work hours and stroke seemed stronger for people under the age of 50,” said study author Alexis Descatha, M.D., Ph.D., researcher at Paris Hospital, Versailles and Angers University and at the French National Institute of Health and Medical Research. “This was unexpected. Further research is needed to explore this finding.”
 
This study supports other evidence linking long work hours to significant health impacts including a study by British researchers published in the journal Lancet in 2015 showing those working 55 hours or more per week had a 33 per cent higher risk of stroke than those working a 35-40 hour workweek. Further research found excess risk for diabetes in women working long hours. Evidence also links long work hours to excess injury rates along with stress and related mental injuries.

Psychosocial hazards and stress 

Although this most recent study did not seek to identify specific reasons for the excess risk for stroke, the researchers did offer some “causal pathways” beyond just longer hours of work—a recognized work stressor. They cite studies showing owners, executives, managers, professionals and farmers faced lower risk for stroke than others. These workers, noted the researchers “generally have greater decision latitude than other workers, perhaps accounting for the smaller effects in these groups.”
 
This hypothesis supports previous research suggesting work stressors including low job control are contributing factors for stroke and heart disease.
 
Researchers from the Harvard Business School and Stanford University published a scientific review of more than 200 studies and found work stressors including long work hours and lack of job control increased the chance of early death in exposed workers by 20 per cent.

Prevention through workplace intervention 

These same researchers note many employers continue to focus almost exclusively on behavioural lifestyle and health choices as a means of coping with stress. Little attention, they say, is paid to prevention through identifying and eliminating workplace causes of stress such as long work hours and lack of job control.    
 
Furthermore, targeting behavioural issues, fails to assist Ontario employers in meeting their significant legal obligations to protect workers. Chief among these obligations is to prepare and review at least annually a written occupational health and safety policy and program(s) that should include a commitment to providing a workplace that promotes worker well-being including healthy hours of work.
 
Employers will also want to consider working long hours on a regular basis for many workers will become counterproductive and detrimental to work outcomes. This includes the growing issue of constant connection to work through email, texting and other forms of communication.   
 
In a press release announcing this most recent study, Dr. Descatha suggests he will take preventive steps himself as a clinician who works long hours. “As a clinician, I will advise my patients to work more efficiently and plan to follow my own advice.”
 
With almost 1.4 million Canadians having worked more than 50 hours a week, on average, last year (2018) many workplaces will want to revisit workplace policies for hours of work.  

WHSC training supports prevention 

For our part, Workers Health & Safety Centre continues to assist workplace parties with training programs designed to help them play a more informed role, seeking prevention solutions around the issue of unhealthy work hours and other workplace stressors. Additional resources, including work hours and shift work fact sheets also help prompt preventive actions for healthier work.
 
To learn more:
Call: 1-888-869-7950 and ask to speak with a training services representative
Visit: www.whsc.on.ca
Email: contactus@whsc.on.ca