Demanding physical work may boost a person's risk of heart disease, two new
"Physicians know that high stress can be associated with increased risk of
heart disease," said one expert not connected to the study, Dr Lawrence
Phillips, a cardiologist at NYU Langone Medical Center in New York City. "These
two studies suggest that, in addition to normal life stressors, the physical
demands a person experiences in the workplace can independently increase their
risk as well."
"The reason for this [labour-linked risk] is unclear, but might be related to
higher stress levels," Phillips said.
How the research was done
In one study, researchers looked at 250 patients who had suffered a first
stroke and 250 who had suffered a first heart attack or other type of heart
event. They were compared to a control group of 500 healthy people.
Stroke and heart patients were more likely to have physically demanding jobs
than those in the control group, researchers found. After adjusting for age, sex
and a number of lifestyle and health factors, they concluded that having a less
physically demanding job was associated with a 20% lower risk of a heart event
The findings suggest that people with physically demanding jobs should be
considered an important target group for prevention of cardiovascular disease,
said study author Dr Demosthenes Panagiotakos, an associate professor of
biostatistics and epidemiology at Harokopio University in Athens, Greece.
The results seem to conflict with recommendations that people should exercise
to reduce their risk of heart trouble. But Panagiotakos said the increased risk
of stroke and heart events among people with physically demanding jobs may be
due to mental stress, while exercise helps reduce stress. He also said people
with physically demanding jobs tend to have lower incomes, which might limit
their access to health care.
'Important to know'
The study suggests that leisure-time exercise might be important to "balance
out" the physical stress encountered in laborious jobs, said Dr Tara Narula,
associate director of the cardiac care unit at Lenox Hill Hospital in New York
City. She was not connected to the study.
"This delicate interaction between work and leisure-time activity warrants
further research in order to appropriately guide public health," she said.
The study was presented at a meeting of the European Society of Cardiology,
taking place this week in Rome.
In a second study presented at the same meeting, researchers looked at more
than 14 000 middle-aged men who did not have heart disease and were followed for
about three years on average. The investigators found that physically demanding
work was a risk factor for developing coronary heart disease.
They also found that men with physically demanding jobs who also did moderate
to high levels of exercise during their leisure time had an even greater risk
(more than four-fold higher) of developing coronary heart disease.
Phillips, who also is an assistant professor in the department of medicine at
NYU Langone, said the finding was a bit surprising. "This is a new finding that
was not previously seen," he said. "Further studies to support this finding will
be needed. As with many areas of medicine, a one-size-fits-all approach to
leisure exercise might not work."
Study author Dr Els Clays, of the department of public health at the
University of Ghent, in Belgium, weighed in on the study in a society news
"From a public health perspective, it is very important to know whether
people with physically demanding jobs should be advised to engage in
leisure-time activity," Clays said. "The results of this study suggest that additional physical activity during
leisure time in those who are already physically exhausted from their daily
occupation does not induce a 'training' effect but rather an overloading effect
on the cardiovascular system," Clays said.
On the other hand, the study did find that men with less physically demanding
jobs were 60% less likely to develop heart disease if they exercised during
their leisure time.
"Further studies will be needed to find out the cause of increased heart
disease in those people who have high physical job demands," Phillips said.
Both studies could point only to an association between hard physical labour
and increased heart risk, not a cause-and-effect. Studies presented at a medical
meetings typically are viewed as preliminary until published in a peer-reviewed
The US Centers for Disease Control and Prevention has more about heart disease.
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