My sister has suffered very severe grief over the recent passing of her husband. Could this actually harm her physical health?

Yes. For example, in one recent study, physicians tested the blood of 80 newly bereaved adults (average age 66), comparing their cardiovascular risk factors with those of 80 adults who were not bereaved.

Result: Within two weeks of the loss of a spouse or child, three measures of inflammatory and clotting risk increased significantly. Six months later, the overall risk dropped but still tended to be higher than the non-bereaved. The higher clotting levels may be related to increased stress hormones, as well as behavioral changes, such as reduced sleep.

Anyone who has recently lost a loved one should take care of his/her heart by getting regular sleep, eating well and avoiding smoking and other cardiovascular strains.