Doing too much overtime and not getting enough sleep may put workers at an
increased risk of heart attacks, scientists in Japan have concluded.
Researchers at Kyushu University in Fukuoka studied the cases of 260 men
aged 40 to 79 who were admitted to hospitals suffering from acute myocardial
infarction (AMI) between 1996 and 1998, and measured their results against a
They found there was a link between the amount of hours and overtime worked
and the increasing odds of suffering AMI.
Men who worked more than 60 hours a week doubled the risk of suffering a
heart attack than those working 40 hours or less.
A lack of sleep (fewer than five hours a night) and a frequent lack of sleep
(two nights or more a week on fewer than five hours) were also associated with
a two to three times greater risk of AMI.
"Overtime and insufficient sleep may be related to increased risk of
AMI," the study concluded.
Occupational and Environmental Medicine 2002;59:447-451