'Work stress can kill'
2008-01-23 07:23
London - Work really can kill you,
according to a study on Wednesday providing the strongest
evidence yet of how on-the-job stress raises the risk of heart
disease by disrupting the body's internal systems.
The findings from a long-running study involving more than
10 000 British civil servants also suggest stress-induced
biological changes may play a more direct role than previously
thought, said Tarani Chandola, an epidemiologist at University
College London.
"This is the first large-scale population study looking at
the effects of stress measured from everyday working life on
heart disease," said Chandola, who led the study.
"One of the problems is people have been sceptical whether work stress really affects a person biologically."
Heart disease is the world's leading cause of death. It is
caused by fatty deposits that harden and block arteries, high
blood pressure which damages blood vessels, and other factors.
The researchers measured stress among the civil servants by
asking questions about their job demands such as how much
control they had at work, how often they took breaks, and how
pressed for time they were during the day.
The team conducted seven surveys over a 12-year period and
found chronically stressed workers - people determined to be
under severe pressure in the first two of the surveys - had a
68% higher risk of developing heart disease.
The link was strongest among people under 50, Chandola said.
"This study adds to the evidence that the work
stress-coronary heart disease association is causal in nature," the researchers wrote in the European Heart Journal.
Behaviour and biological changes likely explain why stress
at work causes heart disease, Chandola said. For one, stressed
workers eat unhealthy food, smoke, drink and skip exercise -
all behaviours linked to heart disease.
In the study, stressed workers also had lowered heart rate
variability - a sign of a poorly-functioning weak heart - and
higher-than-normal levels of cortisol, a "stress" hormone that provides a burst of energy for a fight-or-flight response.
Too much cortisol circulating in the blood stream can damage
blood vessels and the heart, Chandola said.
"If you are constantly stressed out these biological stress
systems become abnormal," Chandola said.