Recently-bereaved people have heart rhythm changes which may make some of them more vulnerable to health problems, say researchers.
The University of Sydney study, released at a US heart conference, monitored the hearts of 78 bereaved spouses and parents.
They beat faster on average than unaffected volunteers, with more common periods of very rapid heart rates.
A UK specialist recommended check-ups for those with-existing heart problems.
It is known that the trauma of bereavement can mean an increased risk of heart attacks and strokes in the months immediately following the death of a close relative.
The Australian team asked people whose relative had died in hospital two weeks earlier to wear heart monitors 24 hours a day to try to reveal any underlying changes which might be contributing to this.
They found that the average heart rate following bereavement was 75 beats per minute, compared to 70.7 in unaffected volunteers.
However, this was accompanied by twice the normal number of periods where the heartbeat accelerated to higher than normal levels, called tachycardia.
This alone does not cause serious heart problems - rapid heartbeats can be a normal by-product of stress and anxiety.
Lead researcher Dr Thomas Buckley said that it might, however, be enough to trigger an attack in someone with pre-existing heart disease.
"While the focus at the time of bereavement is naturally directed toward the deceased person, the health and welfare of bereaved survivors should also be of concern," he said.
"Some bereaved, especially those already at increased cardiovascular risk, might benefit from medical review, and they should seek medical assistance for any possible cardiac symptoms."
Return to normal
The study found that, six months after bereavement, heart rhythms had returned to normal.
Dr Richard Stein, from New York University School of Medicine, said that the study was an "important first step" to understanding how bereavement could affect health.
He said that, wherever possible, the bereaved should try to take moderate exercise and seek out social support.
He said: "Understanding that this is a high risk time, perhaps paying a visit to your doctor, having your blood pressure taken, looking for other illness problems, is an important thing to do.
"In the context of grieving it's hard to do that, but the tragedy of a death of a loved one would be an even greater tragedy if it preceded your own serious illness."
Psychiatrist Dr Colin Murray Parkes, an advisor to bereavement charity CRUSE, said that it was important for bereaved people not to panic if they felt an increased heart rate.
He said: "An increased heart rate can be a perfectly normal response to the anxiety of being bereaved.
"If you are worried, then consult your doctor, but not with the assumption that anything is wrong.
"If you have pre-existing heart disease, then you may well benefit from a check-up at the time."