People who suffer from depression could be twice as likely to have a heart attack compared to people who are not depressed, suggests study.
A new study led by Concordia University has found that depressed individuals have a slower recovery time after exercise in contrast to those who do not suffer from mood disorders.
These findings suggest that a dysfunctional biological stress system is at play among depressed individuals.
"There have been two competing theories as to why depression is linked to cardiovascular disease," says first author Jennifer Gordon.
"Depressed people may have poorer health behaviours, which may in turn lead to heart problems. The other possibility is physiological: a problem with the stress system known as the fight or flight response."
"Our study was the first to examine the role of a dysfunctional fight or flight response in depression in a large population."
A total of 886 participants, who were on an average 60 years old, took part in the study.
Approximately 5 per cent of participants were diagnosed with a major depressive disorder. All individuals were asked to undergo a stress test after which their heart rate and blood pressure were recorded.
Recovery heart rates and blood pressure levels were compared between depressed and non-depressed individuals.
"We found that it took longer for the heart rate of depressed individuals to return to normal," said senior author, Simon Bacon, a professor in the Concordia University Department of Exercise Science and a researcher at the Montreal Heart Institute.
"Heart rate recovery from exercise is one way to measure the fight or flight stress response. The delayed ability to establish a normal heart rate in the depressed individuals indicates a dysfunctional stress response.
"We believe that this dysfunction, can contribute to their increased risk for heart disease," Bacon added.
The study has been published in the journal Psychophysiology.