Those long hours on the job may mean extra money in your pocket, but they may also have some unexpected consequences.
A recent UK review of multiple studies found that people who worked longer hours were at an increased risk of both stroke and heart disease.
"Employees who work long hours have a higher risk of stroke than those working standard hours; the association with coronary heart disease is weaker," wrote lead study author Mika Kivimäki, PhD, an epidemiologist and psychologist at the University of London, and colleagues. "These findings suggest that more attention should be paid to the management of vascular risk factors in individuals who work long hours."
Dr. Kivimäki and team looked at data on adult men and women in Europe, the US and Australia to determine whether working long hours increased the risk of heart disease or stroke.
The heart disease group included 603,838 men and women who did not have heart disease when this study began. The stroke group included 528,908 men and women who had not had a stroke when this study began.
Participants were divided into two groups: one that worked standard hours (35 to 40 hours per week) and one that worked long hours (55 hours a week or more).
As hours increased, so did the risk of stroke.
Those who worked 55 or more hours a week were 1.3 times more likely to have a stroke than those who worked standard hours. The risks were the same for both men and women.
Working long hours was also linked to heart disease risk, but the link was not as strong.
According to Dr. Kivimäki and team, repeated triggering of the stress response — also known as the fight-or-flight response — may be responsible for the increased risk. Physical inactivity may also play a role.
The US Bureau of Labor Statistics reports that average hours for US adults in July 2015 ranged from 26.3 hours per week in leisure and hospitality occupations to 43.9 in mining and logging. Average overtime was about three hours a week.
This study was published in the August issue of the journal The Lancet.
Agencies from several countries, including the Medical Research Council, The Finnish Work Environment Fund, the Swedish Research Council for Working Life and Social Research, the German Institute for Occupational Safety and Health, the Danish National Research Centre for the Working Environment, the US National Institutes of Health and the British Heart Foundation funded this research.
No conflicts of interest were disclosed.