After an argument with my husband over a careless remark he made, I refused to forgive him even when he offered a sincere apology. For the rest of the day, I let my anger churn and seethe, and eventually I got a killer headache. Nourishing my anger was hurting me not only emotionally, but as several studies show, it was also harming me physically. But forgiveness, like so many things in life, is usually easier said than done.

People can hurt us in a million ways, and forgiveness is a challenge. To make it easier experts suggest this: be clear to yourself that you’re not condoning what someone has done. You’re really saying “That’s in the past. I can move on without feeling anger and live in the present as a happier person.”
Are you a ""marital martyr""?
If you’re still having a tough time accepting an apology, it might help to know how much you can get out of it. Why forgive? Because …
It’s good for your heart. A study from the Journal of Behavioral Medicine found forgiveness to be associated with lower heart rate and blood pressure as well as stress relief. This can bring long-term health benefits for your heart and overall health.
A later study found forgiveness to be associated with improving some important measures of health: physical symptoms, sleep quality and fatigue. It seems that the reduction in negativity gained by forgiving increases all around health.
A third study, published in the Personality and Social Psychology Bulletin, found that forgiveness not only restores positive thoughts, feelings and behaviors toward the offending party (in other words, forgiveness restores the relationship to its previous positive state), but the benefits of forgiveness spill over to positive behaviors toward others outside of the relationship.
Plus it improves our immune system response. Chronic anger, hurt, guilt, and hostility can have a debilitating effect on us since these toxic emotions create an avalanche of stress hormones. For example, cortisol, one of those hormones, makes you feel speedy, tense and overwhelmed--and in the long run, heightened cortisol levels impact the immune system. Recent studies have shown that excess cortisol levels impair your cognitive ability and damage cells in the memory centers of your brain.
By the way, once I accepted my husband’s apology and forgave him, I literally felt a release wash over me. It was no fun staying angry and so much more pleasant to let go of anger – and my headache.
(Source: ThirdAge.com)